I'm a gold level player (i.e. bad) so take what I say with a grain of salt, but what helped me most was just watching pro matches of various lengths, so I can just get ideas of how to make things work. When I start out a game I have ideas of what I want to do, and after scouting that solidifies a bit. Then I have some idea after the early game what I want to work to towards the mid or late game.
For example, vs Terran I like to open with 3-gate robo. Past the initial push around that 7 minute mark is the time where I get my expo and just try to macro up a bit. For the midgame, some things I want to do is get chargelots, add gateways, and get a forge up. I try to stay adaptable though, like if he tries to do some banshee harrass I'll get up a stargate and put up Phoenixes, meanwhile defending with Observer/Stalker/Cannons. My late game goal is to get HTs and then harrass him as much as possible. Most of my games haven't gone past the 20 minute mark though, so I don't have too much experience here with the like 3-4 expo battles.
But pretty much I watch pros to see all the potential things I can do, then keep the ones I like in my mind and set goals for what to do in the mid and late game. Right now I only know a couple builds per match-up though.
oh, and if people haven't gotten 2 UMS maps for training they really should, they're both awesome.
YABOT—Yet Another Build Order Tester. You choose your race and a list of build orders, and you can play out the first 10 (or 20 if you set it to that) minutes of a game vs. a Green Tea AI (it's pretty smart) to just solidify the build order and see how fast you get stuff out. It helps you feel comfortable with the first 10 minutes of the game.
Multitasking UMS—You have a probe on one side of the map, and then do a standard game vs a Terran on the other side. You can change the difficulty settings, but in general you have to keep your minerals below a certain amount, keep your base energy below a certain amount, keep your probe alive on one side from a chasing zergling (it's just slow enough that it won't catch up to you going in a straight line or making smooth turns, but making waypoints will let it catch up and kill you), rescue someone via dropship X number of times, and then push against the Terran base and win. The Terran will send in harrasses or pushes depending on what difficulty you're on.
I can't even complete the multitasker on very easy, but it helps me a lot with warming up and keeping my attention sharp. I've only done it for like 2 days at this point, but what happens is that I fail pretty early, keep a note of the things I need to do, and I do so much better the second time.
but anyway go get those two maps because they help with practice a lot.
