Welcome to Dream Views, Geo! We're glad you joined our motley crew of ruffians (We're not really ruffians. That just sounded like the right thing to add to "motley crew")

Anyway, as nesgirl said, already having had a lucid dream will increase your chances of having others. Just keep working towards it, have confidence that it will happen (because it will), and relax. As for your fear of heights, that's one thing you can use lucid dreaming to help with. If you're flying, try to get someone to go with you to help you out and encourage you. And you said you have a hard time stopping once you start going up? Try not going up, but just flying parallel with the ground. Or, focus on a particular point below you as a reference point and keep it in your mind that you're not going any farther away from that spot.

If you're feeling adventurous, though, keep going up. See where it leads.

I hope this was helpful. If you need anything else just let us know! Sweet lucid dreams!

-Amé