Generally people say to have a mantra that is in the present rather than in the future because if you think "I am going to realize I am dreaming" then even if the though gets through in a dream, you are waiting on a future time to LD. It would be good to change it, mine is "I am dreaming" and if ever the thought pops in my head in a dream, you can see how this would help.

I do multiple WBTBs each night and I think that it helps a lot!

usually there is no "random lucid dreams" you have your awareness and recall high, but stress can inhibit lucid dreams. So when people give up on lucid dreaming, the stress goes away and your awareness is still there for a while. This leads people to think that "not doing anything" is what gets them a lucid. I would recommend finding a perfect amount of working on LDing and not stressing about it.

I would recommend reading some of this stuff:
http://www.dreamviews.com/attaining-...technique.html
http://www.dreamviews.com/general-lu...s-secrets.html
http://www.dreamviews.com/dreamviews...ng-sensei.html