To be fair it's all about routine. Like right now, SC2 is a major stressor for me. Need to get into practice again before ladder.SC2 is just tense. Once you get higher it feels like you're on a clock constantly and missing a step anywhere along the way will lose you the game. And then your armies fight and you're suddenly micromanaging the army field on top of everything. :x
My personal approach: Starcraft 2 is like music. No use trying to play a tune when you can barely handle the instrument. So I start by learning an all out macro style vs hard CPU (vhard constantly does hard 1 base timings which is just stupid) and try to expand and max army at the same time until it's a non issue. And as Zerg, Creep spread on top. Fun challenge, see how fast you have 3 full bases with 200/200 army. Never supply block, never float resources, find good curve for army vs expand.
You can of course jump straight into ladder and learn there but that's going into a boxing ring without sparring and practice: you really wanna do that?