Welcome! More people should be interested in Lucid Dreams, it's great. I think the practice of techniques and things required to become lucid also helps you live a better life. Mainly because reducing stress is part of it. A dream journal is definitely the way to start. Improving recall is the first step for any new dreamer. Who cares if you can become lucid if you can't remember it, haha.

I know what you mean about nightmares. A few times when I was younger I used to have horrible terrible dreams and a few times I have managed to wake myself up. I never bothered to look into it before because I wasn't very old and had no access to the internet. Now I'm trying to become more spiritually aware. I can tell you from experience that having a lucid dream is like having chains lifted from you.

Sweet dreams and good luck!