Generally speaking, all these things are dependent on skill. Really, there is no getting around a minimum time of practice if you want to get better. At some point you'll get to a point where you have insight into all strategic aspects of the game. That's when you can only improve through playing and playing even more.
Final thoughts and prospect
I know that most of the content of this guide is obvious. This isn't intended to share that I just learned the basics of RTS nor to show off that I can write mathematical formulas. I want to encourage and sensitise the newer players of you to reflect about what units you build.
Part two of RA3 in theory will be a video commentary analysing Tingu's play style. In order to understand what I'll be talking about you should read this guide carefully because many terms used here will appear in the video.