It was a class on sleeping+dreaming, an “easy A” class that was actually really interesting. Taught by William Dement, an old timer who helped pioneer the field of sleep research. As I recall there wasn’t much emphasis on what dreams mean — it was fairly matter-of-fact in that regard, which I liked.
The journal process, from what I recall, was just to write down every detail. In doing so you may realize patterns in your dream — recurring objects or themes, or anything really.
Another thing, especially for lucid dreaming, is to do “reality checks” throughout your (waking) day. This can be something like looking at a watch. Get in the habit of this — just randomly looking down and verifying that your watch is reading a valid time, and ask yourself if this makes sense, and if you’re dreaming. Most of the time you’ll look at your watch, say “yup 11:42, and I don’t think I’m dreaming.” The idea though is that this will be a habit that you perform in your dream, too — and hopefully, in your dream, your watch won’t make sense, you’ll ask yourself if you’re dreaming and boom! Lucid dream.
For me, lucid dreams were usually pretty short — as soon as I realized I was dreaming, I’d only have a little time before waking up. I also found it frustrating that I couldn’t always control my dreams, so I’d try to fly, and… nothing. Even though I knew I was dreaming.