A good idea when starting a game is to create your basic resource count of three mass extractors and power generators. After which create a factory and create a couple enginers to start to go and build structures and a basic defensive line while your commander creates factories outlines by power generators. Also add at least two power generators for every tech one mass extractor and have them in an L shape so you can build a factory in the L to add power income and speed to the factory and its build time. Once this is done check on your enginers and make sure that they always have something to do, wether that is to create defenses, collect resources, or building factories.
Defensive lines are very important especially sense theres no cap to how many you can have. build a line (that are spaced out) of ground defenses and in the gaps and slightly behind them place AA turrets. by now if you have been building and upgrading then you should have a decent size force. Create a radar in all corners of your base with defenses and power generators surrounding it because they have a very small health bar.