The moment you start to understand your character is the moment you'll use their spacing tools more effectively. Scarlet's F3 is a great anti-air and will catch anyone off guard that is a bit further away. Not to mention it has a ridiculous range. I check my opponent with it, like you awake buddy WHIP!
Bait them in blocking low and they'll just turtle so you throw an overhead their way and they'll start being more careful and block standing and that's when you shake up their world again: grab 'em. Rinse and repeat this cycle, use F3 to control the space and show them you're not messing around.
Also, you can connect a combo off a jump 3 so when you have the opportunity to do so, it's worth it.
Wake-ups are perfect, I absolutely love them. 1-2 to get a full combo and 3-4 to reset. I'm not sure if everyone has the same frame data with those but with Scarlet's U3 they have time to block after the hit as there's a significant pushback. I think you can follow up with a special, but it's best to just back up and F3 again.
Man, this game is amazing. Seriously, I cannot freaking wait to play Cassie.