I had my last two lucid dreams when I wasn't trying particularly hard to have any. I still wanted to have lucid dreams, but I didn't put any effort into any particular techniques. I just went back to sleep, vaguely thinking that I would like to have a lucid dream, but not really caring if I didn't.
I think it is easier to have lucid dreams with this mindset because then I'm not worrying, or thinking too much about it, so I'm not creating the mental blocks that I usually have.