Here's some advice that I've thought of that I am also going to use myself.

I'll just call it conditioned response for lack of a better name.

Decide on a technique that you want to use, or possibly combine several techniques together.

Then, continue doing these techniques every day, trying to improve on them a little bit every day.

Don't worry about having a lucid dream for now. Just concentrate on the techniques you are using, trying to improve on them a little more everyday.

Be sure and reward yourself for the improvements you have made in the techniques you are using, and feel good about the improvements you are making in the techniques you are using.

If one of your techniques is relaxing or self hypnosis, just try to become more relaxed or in a deeper state of hypnosis than the previous day.

And then congratulate yourself on the improvements you have made on whatever techniques you are using.

By concentrating on improving your techniques instead of trying to become lucid, you should find it easier to stay positive, and will be working toward the ultimate goal of being able to become lucid whenever you want.