In response to your question, Zelcrow, the main thing that contributed was time and experience. It was a good 4 years or so until I was able to become familiar with the "dream feel". I'd say the other main factor was simply awareness. I used to try to remain conscious of the present moment throughout the whole day (ADA). It's a noticeable shift in presence and sensation when you slip into a dream, because you lose that strong feeling of a "connection" to an external world with external stimuli, alongside a state of alertness. This was what I used to trigger my lucidity. My "reality checks" during the day turned into becoming lucid in waking life instead. Inevitably this would fizzle out as soon as I'd become distracted, but would periodically return whenever I would have that cue to perform a reality check.