Most Helpful Girl
Start off with a simple "Hi!". I know that I don't ever like to text someone first because I feel like I'm always bugging them, so I feel really nice when they initiate it. Try and watch for negative signals, like consistently late responses, or short answers. Other than that, just go for it. If you ever need a conversation starter, I would recommend playing a game, like truth or dare, or the questions game.
(Truth or dare is fun over the phone because you send pictures/videos of the dares and so you can keep them forever! Bwahaha!)0