So, 1st movie: Obi Wan and Anakin meet. Each of them has as friends Owen and Bail. Anakin saves Padme from something. You stablish what the clone wars are and who is the main bad guy. There can be some other Jedi or creature or funny character, maybe Bail is funny (in a different way Han Solo was)... Maybe a funny villain? Anakin and Padme kiss. All of them together kill the bad guy.

As simple as that.

Doing that will allow you to have all your plot elements covered. That way you can do WHATEVER you want on the second and third movie. Maybe you can make a plot that isnt just an excuse to lead to A New Hope. Maybe something even... ORIGINAL.