Look I'm going to try and be really honest with you here.
The Mike Mann's of the world (google it) have bought out anything useful in the .com domain industry. The rest of us have picked up the scraps hoping to catch the few dollars the so called kings of the industry have missed.
So when you hand register new domains chances are they have not nor never will be a viable domain. The only real chance you have is to look at TRENDING subjects in the news and on
https://trends.google.com/trends/?geo=US
When any new term, item, politician, satire... anything of any substance comes up jump on it and register a domain.
I remember when covfefe the misspelled twitter word from donald trump came up some fast guy snapped up covfefe.com. I actually offered him 5k for it because I had a satire website planned but he did not sell and held out for a bigger payday. Today he lists it on Sedo and 200 bucks is his highest offer. So he should have taken the deal and kept on with new trends.
That is my advice to you. Personally you can go to the poor house trying to hand register random combinations. It may not feel like it at first but renewals crop up very fast.
Anyways.... good luck to you