How to stop the "head" imagination and focus on hynogogic images instead

Last night I tried WILD and it worked for the first 2 times so I was very motivated to try all night. In and out of LD after LDs..

However, for the 3rd time onwards, I wasn't able to concentrate on the hynogogic images as much as I wanted to. I keep falling asleep with taking over having random images in the head (just like falling asleep for a dream)

So I went like this: Focus on hynogogic image -> doze off with random image in dream (causes me to lose focus) -> tried to focus on hynogogic again -> repeat

I fell asleep after having normal dreams.....

Any tips?