If I ever finish my guide on ZSS you could give it a look over, but sadly, it's been a long time since I touched it, lol.
Anyways, first and foremost, MASTER HER RECOVERY. I totally agree with Snakeee on this one. A large part of ZSS's game is good edgeguarding, and you have to be confident that you can make it back to the stage and not get a stock behind because of some stupid SD.
Quick recovery tips:
- Save your doublejump for last, it's the best recovery you've got, it's unpredictable and has the highest vertical distance.
- Clear the edge before tethering, use a u-air or something fast to get the edgehogger away.
- Remember to always boost your double-jump (using up-b directly after you jump)
- If you have the choice to try for a spike and die, or footstool and live. ALWAYS FOOTSTOOL.
After you've got that stuff down, it's really all about mobility and spacing. Like Snakeee said, a defensive ZSS is at a disadvantage. She doesn't have great options out of shield, subpar at best. Know how ZSS moves, her short hop height, her full hop height. Know the length of your Up-B and Side-B. Know when you can chase someone, when you can't. Learn to read airdodges, it's extremely important when trying to juggle combo.
Once you've got your offense, you need to cover the flaws. Get better at being under shield pressure. Understand that shieldgrabbing is no longer the best option. Try doing different attacks out of shield: tilts, aerials, jabs. Understand when someone has enough lag to punish, and when you need to just GTFO and start re-spacing.
Lastly, post on the boards! OP was intelligent and informed, and believe me, it's appreciated. We could use another ZSS regular! d:
EDIT: oh yeah, I forgot. Play with items! It sounds funny, but suitpieces are a HUGE part of ZSS's first stock. If used properly you can get a pretty **** good lead, then all you need to do is keep it!