I am a very new user and I occasionally hit the same brick wall and was doing the same thing you are, screen shot, etc. I then found this video on youtube...
https://www.youtube.com/watch?v=Vz_kTUeaf1k
I found it from a link on the logic puzzles site somehow, but I can't find it again. Anyway, in the video there are two "advanced techniques" discussed. If you employ the "advanced techniques" when you hit a brick wall, you will never have to resort to trial and error.