Fast expand if I can, into a macro-heavy play building a huge army, while keeping note of the expansions around the map to control resources. Know the location of their army, scout them early and frequently, react to their army comp and build a counter. Macro like a fucking god because if your units are evenly matched counter-wise more shit>less shit, and be as greedy as they let you. If they turtle, you starve them. If they're super greedy, you harass, darting in and out because they can't defend everything at once. If they play safe, then you have to put effort into scouting and find out what you can counter them with. Keep a presence on the map, make them feel like they're under a lot of pressure, it'll screw with their head. Know what's standard in the matchup you're playing, so you have a starting point to go from with your opener and your scouting.
I could go on for hours, but I'm gonna just cut this off here.