you can charge R and then flash to catch people off guard. i.e. from walls, or while chasing someone (to get slow or stun if lucky). Works best if they think you're running away. You can also R backwards and flash behind them.

you need to throw out autos in between Es while chasing someone. This has the biggest effect early game.

If your laner just left lane to go roam, warn the lane and push your wave as often times you wont have the mobility to follow up, and having their wave pushed in can make them come back. Additionally, you can push and look for a TP.

Learn to use miasma effectively, it is by far her most versitile ability.

Try not to rely on the stun from her R, good players will turn around.

I am a cassiopeia OTP. I was drawn to cassiopeia from her challenging mechanics. As most of us cassiopeia mains will agree, the difference between being a cassiopeia and a random snake is landing abilities. In order to get multi kills and such you need to chain your Qs and space like a madmad. When I was finally able to play her well, it gave me lots of adrenaline to pull of flashy plays, and kite well, and in turn helped me become better at this game. I started only playing cassiopeia, learning matchups, getting better and better and better, until eventually I realized I was a OTP and I gave in.

A couple seasons ago with the item changes, Cassiopeia was hit hard. She essentially needed to spend an extra 3000 gold to get into the game, and along with meta changes to favour earlygame comps, constant nerfs to items, runes, and the sustain system, and burst damage going up, she has become very difficult to play, often being a situational pick. Being an OTP, I was forced to adapt in any way possible. Often times you will see cassiopeia mains suck it up and build liandries into seraphs, I couldn't stand that build so I made a couple of my own. I will admit that my builds might not be superior to the standard, but It does retain my playstyle from when I learned her. Overall, I'd say that if you tried cass and didn't like her, try one of my builds. Additionally, if you already play her, it might teach you a thing or two to utilize muramana.

Sincerely, Flippy.