I suggest making a mouseover focus macro. Then make focus polymorph macros. Also make mouseover polymorph macros. I reccomend getting the addons bg targets, a interupt tracker that shows cds on nameplates, and say sapped.
Also make a /stopcasting blink macro and /stopcasting frost nova macro, very useful for stopping midcast to perform the spell, cannot play without them tbh.
Start turning with your mouse and moving by holding both mouse buttons down. You can keybind the strafe left/right to whatever you want I prefer "a" and "s". You can hold down the right mouse button and pivot while casting. You can hold down the right mouse button to strafe while moving. Go into keybindings and set interact with mouseover to scroll up and down. This is how you click on flag picks/returns the fastest.
Just a few tips.