I wouldn't put my bet on WILDing being easier. WBTB is the only method I even try anymore. I WILD by accident a lot.
First of all don't use contractions when you say that you will lucid dream. Sounds silly. I know.
If you are falling asleep, you have not slept enough for the night, OR you have not waited enough before laying back down. (in my experience). It also helps me to lay down in a different room and/or different surface. Try WBTB on the couch.
Saying the words "I will lucid dream." repeatedly isn't nearly as important as beilieving your own words when you say them.