The most popular maps seem to be medium-sized, with relatively open land and 1K/1K resource settings.
This is what this guide will get you started on.

I won't get into what ground plant to build first. Kbot or Vehicle plant, it's your choice. But I will
tell you to never to build an aircraft plant on a medium or small land map. Any reasonably skilled enemy
will swarm in and kill you if he can reach you.

So, here it is -- Orion's magic opening formula to get up and running quickly.
Build two Solar Collectors and your factory of choice. This will leave you with the resources necessary
to build Metal Extractors (now referred to as mexxes) for your plant.
Build a few scouts to see what your enemy is building (and to kill any unprotected mex you come across).
Don’t build any more Solar Collectors until you have at least 200 units of stored metal, or else you might
nano-stall (that is, run out of metal, energy or both while still attempting to construct units, reducing
your building capability to near-zero).
Was that so hard? I see a lot of players do all sorts of weird things, like build four solars, gather a bit
of metal, start on a factory – and then sit there for 3-4 minutes under nano-stall. I’ve seen others go crazy
on mexxes, hoping to support a plant that hasn’t yet been built. These mistakes may seem minor, but at the start,
if your opponent has six units and you have five because he built his first plant a scant 45 seconds faster,
that could be the unit that puts you behind in the resource expansion race.

Which in turn, is the beginning of the end.

The units of champions

These are the offensive units you will build exclusively at the start of the game.

Note that this list
doesn’t include scouts, which are required in different circumstances.

Arm: Flash, Samson, PeeWee and Jethro. Build Stumpies, Rockos, or Hammers for a base assault, or if the
situation warrants.

Core: Slasher, Crasher. Build Raiders, Storms or Thuds for base assaults or for specialized missions.

Core players should also never never build the somewhat weak Instigator until they’re better than most players.
Core players should also consider the A.K. to be the equivalent of the Weasel don’t mistake it as being equal
to the Arm PeeWee, as the PeeWee mounts the same weapon as the powerful Flash tank, while the A.K. makes do with
a somewhat puny laser.

Up Close: The Arm Level 1 Ground Units

Arm Flash
The Flash: Arguably the most powerful Level 1 unit in the game, and with good reason. Up close and personal,
there is not a single Level 1 unit that can beat the Flash. As an Arm player, you should use this unit to limit
your enemy’s initial attempt to expand, overpower defenses not protected by Dragon's Teeth, and to crunch anything
else out of any Level 1 factory in squad-size battles (three to five units).

Arm Samson
The Samson and Jethro: Use this unit in battles larger than squad-sized. Why? Under concentrated fire at long range,
the lead unit of an incoming force will likely die, leaving wreckage for the following unit to maneuver around. As
they move around the wreckage, another salvo will create more wreckage, and so on and so on. When the enemy is close
to reaching you, retreat. He may chew up a few stragglers, but the others will continue to fire on visible units while
retreating. This tactic almost ensures you’ll come out on top in any large battle where the enemy doesn't use anti-air
units on you. Now, it’s a battle of skill.

Arm Jethro
But why use the Samson/Jethro combination instead of the Rocko?

The anti-air missiles used by the Samson/Jethro are guided, and thus do not miss ground units
This same AA missile has a longer range than every weapon used by every other Level 1 unit. And although it doesn't
do as much damage as the Rocko’s rocket (about 20 percent less) the Samson/Jethro will have fired roughly five times
before the Rocko has fired its third shot, thus actually doing more damage in the long run.
As an added bonus, the AA units used in a ground-attack battle force can defend themselves from air attacks.

Arm Rocko
Rocko: This is a unit best at assaulting structures at long range. If the enemy manages to get up a wall of Pulverizer
missile turrets backed up by Light Laser Towers and Gaat Guns, you will need Rockos. Structures don't move, so rocket
guidance isn't a problem. Rockos have better armor than Samsons and Jethros, so they last longer to dish out more damage.
Although Samsons and Jethros do more damage over time, the Rocko’s first strike is often enough to knock out a defensive
structure and minimize counterfire.

Arm Hammer
Hammer: Arm’s Level 1 artillery unit. It will fire over obstacles and works best against stationary targets. Great for
fighting in heavy wreckage or against defenses blocked by Dragon’s Teeth. But there are a couple of weaknesses with the
Hammer you must be aware of.

It must open the breech of its guns before firing. This delay is a significant liability when skirmishing with enemy
troops.

It has a bad armor/cost ratio, making it an unwise investment if there is a chance it will get caught in the open.
The Hammer’s plasma shell is slow; the Hammer will rarely hit anything that moves.

Arm Stumpy
Stumpy: Arm’s Level 1 armored assault tank. Like the Hammer, this unit fires plasma shells over obstacles. It has great
survivability for a Level 1 unit, but it has a few weaknesses as well, making it a bad choice for skirmishing.
A slow rate of fire. Even with the extra armor, a Flash will still beat a Stumpy shot-for-shot simply because of the
Stumpy’s low damage potential.
Poor maneuverability. The Stumpy gets bogged down easily, with a bad turn radius and crummy acceleration. It’s easy to
create traffic jams with Stumpies.
Now, you're probably saying, "Ouch, why would I ever use this unit?" Well, there are a few instances when it should be
deployed. For instance, when I might need to take out a critical target that my direct fire units cannot hit, and I will
likely come under fire while doing so, I'll use Stumpies. The extra armor will ensure that the group of Stumpies will get
in a few shots before dying.

Up Close: The Core Level 1 Ground Units

Core Slasher
Slasher/Crasher: I could copy and paste the Samson/Jethro excerpt from above, but I won't. The same basic description
goes for the Slasher/Crasher combo as well. Just keep in mind that with Core, you'll be trying to prevent an Arm opponent
from boxing you in and creaming your metal resources with Flash tanks.

Core Crasher
Keep your distance from the Flash and dump your missiles into your opponent’s ranks at range. Chances are, in the early
stages of the game, you will have radar coverage and your opponent won't. Use this advantage to the utmost -- you have
nothing to gain by walking into range of a Flash's EMG.

Core Storm
Storm: A great unit for Core, comparable in performance to the Rocko. But again, just remember as Core you'll more often
find yourself on the defensive in the early stages of the game because of those miserable Flash tanks. With the Storm’s
armor being roughly the same as a Flash, you'll find they do wonders as spotters for your heavy base defenses. Even if
the defenses miss their initial shots on incoming enemy units, if the Storms cam interfere with enemy movement long
enough for the defenses to find their mark, the Storm has done its job.

Also, like the Rocko, the Storm makes a great assault unit when you need that extra oomph in removing defenses.

I also see some players using the Storm alone as a skirmisher. All I can say is, sooner or later, you’ll come across
a good player who will use the AA units to cut you apart. If they move on oblique angles, they have four advantages:

Cost. They come out of the factory faster and cheaper, so expect to see more of them.
Better range.
Guided AA missiles don’t miss.
Speed. If you get too close, the AA units can run away and repeat the mulching.

Core Thud
Thud: Like the Hammer, this is a plasma-shell-firing artillery unit. Unlike the Hammer, however, the Thud has several
major advantages, making it a far superior unit.
No need to open its barrels, getting its first shot off much faster.
Mobility -- this unit can climb. It’s great for getting into places the enemy doesn't expect and then raining death
from locations the enemy can’t reach. An example: The Thud can climb the steep hills on the map Show Down. It's
pretty satisfying when an Arm opponent has built its defenses at choke points leading into his base, only to have
your Thuds firing down upon him without fear of retaliation.
Other than that, use the Thud in the same situations in which you’d use a Hammer.

Core Raider
Raider: Comparable to the Stumpy above; use the Raider in a similar fashion to its Arm counterpart.

Core Instigator
Instigator: Simply don’t build this unit. Why, you ask?

The Instigator's laser cannon is severely underpowered when compared to the Flash.
The Instigator is more expensive than the Flash.
The Flash’s EMG weapon has a cone effect, allowing the unit to maneuver at better angles to deliver damage.
Heard enough? OK. One more thing: Between two players of equal skill, two Flashes can easily smoke three Instigators.
And the Flash is cheaper.

Miscellaneous Tips

These are small, little things to remember that can save your bacon.

The Guard command: If you're outside of your own radar range and your units come under attack by an undetected force,
find your unit that is under attack and order the rest of the group to guard it. You'll automatically counter your
opponent’s fire, but you'll have to repeat this process every time you lose a guarded unit. As a Core player, you
can use this tactic to counter submarines operating under cover of the Fibber sonar-jamming unit.

Factory Jam: A tactic of questionable fairness. The Arm Vehicle Plant has a ramp in which you can actually drive a
unit. If the unit is destroyed and leaves behind wreckage, the factory becomes blocked, and units are prevented
from coming out. Occasionally, the wreckage also becomes unreclaimable, blocking the factory from ANY future use.
If you like to play fair, you can drive a unit into the plant and order the unit to self-destruct (usually reducing
an previously unharmed plant’s health by about 33%). You'd be surprised how often I can take a plant out with two to
three units before the enemy can respond.

Indirect Artillery Fire: It's not a bug, it's a feature...If you order an artillery unit to target the ground directly
in front of the unit, the barrel will elevate to the maximum angle. When it fires, the weapon’s range is dramatically
increased, at the cost of accuracy. Want to see this used to the greatest effect? Try it with the Core Intimidator.
The increased range makes it easy to fire on the enemy from the safety of your base.

Get More Stuff: If you are in the middle of construction and the enemy cuts off your resources, stop building immediately
and shore up your resources. It's faster in the long run. Don't laugh – about a third of the people I play will stubbornly
keep building under nano-stall.