Build Orders are fundamental to all Real Time Strategy games. Supreme Commander may have a less intensive build order strategy in comparison, but it still applies to this game.
A build order is simply the time, way or position where you place your buildings, and the order you do so. The units that you build also connect to this, but may not be strictly defined to a build order. Many skilled commanders often have multiple build orders stored in memory to speed up the process and are prepared to adapt them to their situation. A good build order optimizes the resources available later in the match, involving resource and construction mechanics.
This may seem primitive and ineffective to more experienced commanders, but it's surprising how many fresh recruits do not ever learn a build order, which can lead to their downfall and a quick nuclear detonation. To find the best build orders for any scenario, younger commanders have observed replays or operations of the higher ranked commanders.
Note: The instructions here are based in the Supreme Commander: Forged Alliance expansion. Some may apply in the vanilla version, but no guarantees.
A generally recommended build order is the one used by the much older commanders who originally fought in the Infinite War. With a commander's ACU, they build a factory, normally land, as an air factory is very risky as their cost is more inhibitive in extremely early build order which may make a commander meet their maker much sooner. Afterwards, a commander builds a mass extractor, two Power generators, normally attached to the factory, then another mass extractor.
A factory, a pair of power generators, and two mass extractors. Seemingly simple, but at this point, the options begin to get exponentially larger, which can cause problems for commanders as they have too many options.
As soon as construction of the factory is complete, most commanders immediately begin building engineers first, from as little as two to as many as five, depending on the scenario and aggressiveness of the commander. Some commanders also choose to build a reconnaissance task force or wing, with a scout and some light bots and T1 light/medium tanks or fighters and bombers to accompany outgoing units. Overall, it is up to the commander, as they should play to their strengths, and if known, the other commander's weaknesses.
In most maps, the first thing to build is a land factory, with two power generators adjacent to it. Then build four mass extractors (on the four mass deposits in closest proximity to a commander's starting location). After that, build 3 more power generators, then a second land factory, or 6 more pgens and an air factory. Add power as you get more mass income and can spend the power (watch your eco bar!). From your first factory, make engineers, and use them to expand around the map (this means taking mass extractors on the map that aren't in your base). From then on, add factories and power generators as needed with your acu or engineers, and you can build tanks and other units from your extra factories onward to kill your opponent's expansions! If you see yourself stalling power, pause any air factories you have, and have engineers spam power generators till you are in the green again. If you are stalling mass, stop building factories and try to reclaim mass on the map, or expand more!
This generally is a good suit for Seraphim players, but it can make do for other factions as well. First, build a Land Factory. When it is finished, use your ACU to build four Mass Extractors. Meanwhile, build four T1 Engineers from the factory. Then build four T1 Power Generators around the T1 Factory. Wait for the Mass Extractors to be finished, then upgrade the Factory to T2. You will most likely Mass and Power stall, but that's okay. when it is finished, build four Ilshavohs and keep them around your base as a mobile Point Defense. this gives them a significant boost over normal Point Defense, and therefore their veterancy rate will be higher. Continue to build Ilshavohs, then storm the enemy's base when you have twelve or so.