How do you get in the mood for phonesex?

Personally exchanging pictures does the trick to get it started... sending an unexpected video is always nice to, gets the adrenalin pumping for shear unexpectedness =D

When it comes to the actual phone sex convo, I'd say to just simply vocalize everything you are imagining down to the very T... because you're not only panting a picture in your head. Also try and fiddle around with both partners fantasies, with a fantasy both of your imaginations can run wild. It's also a great way to find out your partners deepest curiosities and or fetishes.

Good Luck, I hope I was of help =D