A big change from running is the easy access to hydration. Bring a bottle or two and drink at least every 15 min. You'll love it. (Probably not enough to start jogging with a camelback or anything, but it's a huge boost. )

A lot of runners I know don't use energy gels either. I suggest them at least every 30 minutes.

Oh and you will have a sore butt, it takes some conditioning. But after a few rides don't be shy about experimenting with nose up/down on the seat, or a seat with different shape or width. If you're lucky enough to start with a setup that works for you, that's awesome but it usually doesn't happen that way.