I suggest you watch some of the video series from Fow where he goes from C- to S (and then another series to S+). He's worthy of being watched, and you can see how his gameplay gets better as the series progresses. You don't need to watch them all unless you want.
Here's the first one:
Or unless you are instead asking for some novelty tips and tricks that don't necessarily improve gameplay. I don't have anything to contribute in that way. Just improving your game sense is the best tip/trick I'd suggest.