Take the legs out of your serve to begin with.
Get the ball toss over the left shoulder if you're are right hander.
Practice dropping the racquet behind your head and brushing the back of your hair with the racquet and coming over the ball.
Allow your back to arch and push out your front left hip.
Your finish needs to be on the same side as your arm, this will feel weird, but if you can brush in that motion you'll get more topspin on your shot and will allow you to kick the ball out in the opposite direction. Keeping this finish will help wit that outwards kick.
It's hard to explain without being next to you watching you serve as there are so many technicalities but this should hopefully help