You shouldn't try so hard. If you work very hard for it and it fails you get frustrated and that's the last thing you'd want. You need to relax, indeed read some info on this site, and just think, ok I'm gonna sleep well tonight try the MILD method and have a lucid dream. If it doesn't work then try again next day, it'll come eventually. I found that I have the most lucid dreams when I go to bed relaxed, and not with the thought - will I finally get a lucid dream.

Good Luck,
and some methods just don't work for some people, like mantras do work for me, but apparantly not for you.