I'm trying hard, but I'm not able

Definitely stick with the Dream Journal. It can be a lot of work but this is what helps maintain the connection between your waking life and dream life. Try to enjoy the experience of learning what your dreams are like. Skim over your journal before falling asleep and think about all of the dreams you’re going to remember tonight.

I understand that you haven’t had much luck finding dream signs yet, but that’s okay. I’ve found many dream signs over time but they aren’t really what I use to achieve lucidity in most cases. They help but they are not the only way.

If you are looking for a good recipe for lucid dreaming, I recommend the following three-pronged approach: