2. create a ritual
Even though it should be simple, people make it harder than it has to be. They think too much and try to use a fancy toss with spin, or they change their footwork on the approach. This is why successful jump servers create a ritual.
A ritual is a simple motion, action, or even a phrase you say to yourself every time you jump serve to keep your mind on the action, It's very important because it makes the motion automatic. Think of a golfer having the same routine every time he putts.
I like to take five steps back from the court first. I twirl the ball behind my back and brush the sand off the ball. I toss the ball and take a right-left-right-left, four-step approach, then contact the ball and follow through.(see photos).
Figure out what works for you, then stick with it. It'll help your jump serve become an easy, automatic motion.