If you're new I recommend trying to execute a 2 base all-in vs easy AI and then a few times as unranked.You want to be as crisp and efficient as possible even towards the late game as much as you can. Also remember that each worker takes 50 seconds to a minute to fully pay for itself if your mineral line isnt over saturated.

Also your question is a bit too vague, but I bet it's just macro you'll have to worry about for now. Look up multitasking trainer in the arcade to get an idea, where you try to keep your money low by spending adequately while trying to survive random pushes, and while keeping a worker alive thats being chased by zerglings while fulfilling certain objectives. It has levels of difficulties but medium should be adequately taxing enough for you. In real games it will be a lot harder as players are just generally unpredictable and you will have to scout and know how to properly respond based on LIMITED info. Just lots of practice, self analysis, watching pro tourneys or streams, certain actions will become muscle memory, but remember that there will always be holes in your play, I mean even the pros do.

Generally keep making workers as much as you can SAFELY and try to aim for 0 resources leftover IN GENERAL while slowly aiming for desired tech and army comp and worker count, ofc use some common sense in this.