1. i strongly suggest mastering your technique and battle orders against comps until you hit roughly a 60-70 actions per minute.
2. Micromanagement and Macromanagement are the two keys that ensure your victory. Having good micro means your coordination between your units. I.e. surrounding heros, avoiding getting your heros surrounded, attacking weak units, saving weak units, splitting units into groups and select different targets, etc.
Macromanagement is the game that is outside of battles. Having good macro is ensuring that you base is well built and always producing something (be it farms, units, or upgrades) and expanding.