You need to learn how to use shield more effectively in defensive manuevers. Dashing or running into shield when you expect an attack can earn you powershield and then you can either see what your opponent will do or immediately punish with shieldgrab, nair from shield, fc from shield ect. or get defensive again and roll, wavesdash or sidestep away. Crouch canceling aerials from run is also handy when you're running toward someone who's attacks you can cc.
You need to learn how to use turnips more effectively. Defensive turnips involve spamming and dropping with z-drop on someone's face as you escape and then djc on them with aerial. Attacking turnips infolve many ways of attacking them as they get hit by the turnip and don't forget that turnips works great as distractions as well and when they forgot that turnip was gonna be there, they get hit and you will gain a free hit. Armada does this type of turnip games often. More attacking versions can be found from pc chris's videos, he has a knack of turnip rushing perfectly with no real openings. It involves smash throwing a turnip as soon as you jump from dash so you get enough movement to immediate fast fall and fc attack, or the fast fall can be ignored and double jumps and simple float can be used instead, really good to combo with nair if they fly close and fair if they fly far and on ground, nair into dsmash/dash attack/another fc nair/slap comboes well especially at low% and against fast fallers.
You also need to stop that unneccesary wavedash back movement, such quick version serves no purpose other than occupying your fingers from the real maneuvers you need to do in order to evade and bait someone. Doing the way you do it not only leaves you in the exact same position you originally started, but does not change your position enough between the maneuvers. Start utilising dash dance more in effective manner like cort does and less wavedash, maybe even fox trotting there and there. Peach's wavedash is best utilised when you use the full lenght aka perfect wavedashes and when you use it from shield or quick positioning when you don't want to change directions or when you wanna cc at the same time.
You also need to learn how to predict people better, like how they get up when they have fallen down and where they will go after they got hit. Tech and roll chases are always important no matter the character you play. You can also switch some dsmashes into dtilts and whatever junk you may do, just let go of the control stick momentarily and then do your other actions like grab, shield (very good btw), dash attack or other stuff, even full jump/ fc nairs. You also need to learn how to space properly and you fast fall your fairs too early, L-canceling when jumping to platforms is very important as well, along with being able to perform actions from float cancels as soon as the frame data allows you.
Bold parts are summarised versions, but I suggest you read my post thoroughly to grasp the full concept of my perspective in criticising your video. And now that I viewed your vid, I hope you spare me the same courteus gesture and view some of mine in my own video theard on the first page. :3
