Never Miss Your Serve!
At the pickleball club where I started to play pickleball, when someone misses their serve, everyone says 'Coach Mo says never miss your serve'! It has become a bit of a joke between us all but the truth is, if you cannot get your serve in, you can never score points and it is only the team that is serving that can score! Don't worry too much about varying your serve initially, work on consistency of getting your serve in. Then when you are consistent you can work on variety of serves (high, deep, angled, hard driven, flat). The ideal serve will land nice and deep near the baseline.