My advice is if you can't do WILDs then do something more easier! I know that isn't what you want to hear but doing WILDs is very difficult for most people. I've tried several times and have gotten so close but never done it.
If you want to keep trying then completely relax, go to the toilet, make sure theres no family members or anyone other disturbances ect. Then just concentrate on going lucid, also be positive. It helps to not think about thinking if ya know what I mean