One problem is that the best lucids usualy happen at the early morning hours of the night because the REM periods are longer. So intead of going to sleep earlier as suggested, I think it would be better to do the normal RC of looking at the letter when doing WBTB, and then when you want to induce the lucid, to do the WBTB earlier, so that when you are used to seeing the letter you will be asleep after the WBTB.