Gameplay dos and don'ts

Do

Do get all the metal you can

Metal is needed to get just about anything done in the game, and you want as much of it as you can get. Build Metal Extractors and reclaim wreckage from the battlefield like your life depends on it (because it does), and do your best to keep your enemy from doing the same.

Do use your units

If a combat unit isn't shooting, it isn't paying for itself. If an opportunity to profitably deal damage to the enemy arises, take it. If your team is engaged in combat somewhere, send your units to help out, but don't throw your units away needlessly.

Do use multiple unit types

Using only a single type of unit can result in your opponent replying with a countering unit type. A swarm of raiders could be met with riots, or a lot of assaults could be beaten with a raider force.

Having only one type of unit also restricts your options in battle, and can make some other options unprofitable. For example, using raiders to attack fortified areas will get them all destroyed, and dump a large amount of metal at your opponent's doorstep.

Do build energy resources

Unlike metal, energy is consumed a lot more, especially if you have shields/cloaking units, so the best thing to do is to make a lot of energy structures, next to Metal Extractors or linked into your Overdrive grid. You should always have more energy than metal, or more than you can spend. Excess energy is used to Overdrive metal extractors. Because Overdrive loses efficiency as more power is pumped into a Metal Extractor, it is best to have more mexes on Overdrive than to have few mexes with more Overdrive.

Do have mobile defences

Despite towers being cost efficient and powerful, they can't move, so they can't attack or move to a different location - artillery will make quick work of them. Make some units as a dedicated defence force, so any force entering your territory will be opposed quickly. Raiders are a good choice for response forces as their speed enables a fast response to an attack, as well as being strong against heavier enemy units.

Do use unique unit abilities

Some units have special abilities and weapons, activated with the D key. Swifts have a fast burst of speed, useful for scouting or rapid interception of enemy air units. The Dante has an incendiary missile barrage, good for attacking a shielded and clustered enemy. Scorpions have multi-stunner, good for usage against an opposing heavy unit. Some others units have these "D-guns", so find them all!

Don't

Don't make lots of defences in one place

The enemy will simply go around to where the defences aren't (like where your allies are), and to fortify all possible attack points simply isn't economically feasible. Seed moderate defences where necessary (e.g. at chokepoints), sprinkle light defences elsewhere for defence in depth, and use mobile units for the rest of your defensive needs (or better yet, use them to be the one doing the attacking).

Don't send your units in one by one

They'll just die one by one. You want to concentrate your forces wherever possible; see Lanchester's laws for why.

Don't overconcentrate your units

Concentrating your forces in one place means that an attacking enemy can bypass them at a different place and wreak havoc in your territory.

Don't build volatile energy structures in a large cluster

Building explosive energy structures such as Fusion Reactors too close together makes them more likely to chain explode when attacked. Half of your economy could be instantly destroyed (as well as anything nearby) by a few bombers if your energy buildings are too closely packed.

Don't build volatile energy structures next to anything important

An explosion from a large energy building could severely damage anything nearby. Having, for example, a Strider next to an energy building cluster could be a disaster in the making.

Don't make lots of storages

You want to be spending your metal and energy as fast as you can, not stockpiling them. Storages should only be made under very specific circumstances, usually in FFA matches.

Also, relying on storages gives your enemy a place to directly destroy your resources and hamper your economy. A cluster of storages could be wiped out by a bomber strike.

Don't make more Caretakers than you need

Caretakers can help your factories and constructors build faster, but only if there's metal that's actually available to spend. If you only have enough ingredients for three cakes, having ten ovens won't make them bake any faster than three.

As a rule, you shouldn't build new Caretakers if your current expenditure already exceeds your income. Each caretakers spends 10 metal per second at full speed, so you can easily determine how many you need.

Don't make heavy defences behind the front line

Building a Desolator where it will never encounter an enemy unit is not an effective use of your metal. Try to put heavy defences directly on the frontline or near the frontline where they can fire on enemy units. It is okay if you build heavy defences further from the frontline if the front is starting to fail as a means of stopping a complete collapse.

Don't use terraforming more than necessary

Terraforming isn't cheap. Try to be as stingy as possible with it. Don't terraform a huge plateau just for one Big Bertha. If you need to terraform a platform for something, hold click when placing it and use that tool to help you.

Don't stall the game after you can't win

That's just impolite, so resign like any other decent player.

Don't morph your commander excessively

Commander morphs quickly become useless after a few morph. The simplest way to avoid over investing in your commander is to limit yourself to 1 morph only unless you are very, very confident that it will make cost.

DO have fun, respect your teammates, and enjoy all that the game has to offer.