I am a platinum player who recently switched to random

I would say the main thing is to focus on mechanics and macro (assuming you know the hotkeys and functions of the units of all three races).

The main thing that is helping me is to watch lots of pro VODs with knowledgeable commentators. This has allowed me to get some basic intuitive feel for what compositions go against what, when to expand, etc. It is also a good way to find builds of course.