If picturing Donald Trump works for you, great, but I can't imagine that I could switch off my thoughts in the way you do if I was picturing that particular face. 
Actually, I've tried all sorts to help me drop off, but still haven't found a method that routinely works for me.
Methods that involve using my brain, such as counting backwards, or going through the alphabet thinking of names that begin with each letter, don't work for me.
Quite the opposite - once my brain is involved in an activity like that, it goes into everdrive and won't switch off again!
I now listen to audio books when I go to bed, and often go to sleep listening to those although I switch it off if I feel myself starting to drift off.
Uunfortunately, though not surprisingly, the boring books ones are much more effective!
The trouble is, even though I set a timer for the audio to switch off after, say, thirty minutes, I often spend ages the next day trying to find the place in the book where I must have fallen asleep.
In fact, I don't know how it happened, but I once 'missed' about three hours of a story and didn't realize for several days.
If I wake up in the night for some reason, which I do most nights, I try to get back to sleep without the audiobook, but if I reach a point where I am tossing and turning and just can't switch my mind off again, I do now put it on again because if I don't, I know that I might still be awake several hours later.