Roll20

[Grod_The_Giant]

As someone who's been using roll20 for a long time, the best piece of advice I can give you is "use it as sparingly as possible." Don't touch macros or integrated character sheets, don't worry about finding good-looking maps and tokens, don't stress about line-of-sight or initiative tracking or even hit point bars on tokens. Keep using all the same notes and organizations that you're used to using in live games and pretend that roll20 is nothing but a video chat service with a shared whiteboard.

Because while there are a lot of cool bells and whistles, and they can be really useful at times, they're not obligatory. Use what you understand and ignore the rest; you'll save a lot of headaches that way. All the fancy stuff can be picked up bit-by-bit as you go along.