What is the best way to tell someone that you miss them and want to start over again?

I'd take the chance and give them a call. Only you know what the prior problems were in your relationship so if you were part of the problem be sure you have worked it out and learned from it and you are going back into this relationship with a little more maturity. Don't sit there wondering and end up regretting the fact you didn't give it a try. Call her/him up at a decent hour and ask nicely if she/he would like to go for a coffee or a drink. Take it slow and easy and don't push her/him into a corner right away. Slowly tell her/him from the heart how you feel and you'd better mean it! Good luck Marcy