I would say if you have a real desire to have stronger lucid dreams then just keep trying. Try everything you can think of. I've had minimal success over the past 5 months (maybe 3 LDs), so maybe I'm not the best person to be giving advice. But I am determined to keep trying.

Sparkley's advice seems very good to me. Really get your motivation going. Think about what you would like to do in your dreams: flying, time travel, sex. Also reading about it through books and internet will help to saturate your mind with the thought of it.

You know you can do it because you've done it before. Good Luck.