When I have the idea for a video I go to the youtube search bar and start typing in a keyword that is associated with my idea...for expl...say i want to make a video on ranking a video...I will type ranking a video on the search bar.
Next I will go through all the youtube suggested phrases that relates to the video I want to create and look at the competitions on the various phrases.
When I find one that I think I can rank on it... I use it as my video Title
You have to think about SEO for sure.. Do some keyword research first (I recomend Tubebuddy) Great tool for keyword research That being said you you also have to make catchy titles and that can be a bit tricky (yes you would like people to click) And that brings me to thumbnails. If you havent got the best titles you can go far with some great thumbs