What I do is just breath and listen to that, in and out. Nothing else. It relaxes me till the point I will get into a dreamy state and all I have to do from here on is keeping myself focused and don't go wandering on random thoughts. After a while the random thoughts will create a dream and if I don't wander along with those thoughts I'll slip in lucid.

Although if I'm too tired I won't be able to do this because of my exhausted mind, thus no focus.

I hope this will help some people out there who struggle getting lucid =)