This is something that I have thought about a lot for my channel, and I've had good results getting noticed(relatively) with specific, searchable content. What I mean by this is a video with a title that people will search and bring you "organic" views from. According to my channel analytics, 51% of my views have come from the YouTube search bar, and another 34% from Suggested Videos. Getting people to search for keywords in the title of my videos has been my bread and butter.
I think this is sort of what people mean by "make something unique", but not every unique idea necessarily has search demand. If you really want to get into detailed research, you can come up with specific ideas and then use a tool like VidIQ to figure out where there is some demand vs competition, but you can also do that pretty easily without a 3rd party tool as well. You just search the title of your video and see how many other videos are already ranked with the same title. If there are lots it will be hard to get noticed often.
Remember to make specific content, you never want to have a video title that tons of other videos have unless the demand is very high and the recent competition is very low. So don't title a video "Call of Duty Walk-through Part 1" expecting to get a lot of views from the search bar, as there are tons and tons of COD walkthroughs and mostly only larger YouTubers can run very generic titles on keywords with so much competition successfully . You can still make those types of videos and do well, but you want a specific title that says something unique to draw people in and pack more unique keywords with less competition. Showing how to do specific things in a game like tips and tricks, or guides, or challenges, or anything you can put in the title to make it have more unique keywords and less competition is useful. I find there tends to be a lot less competition on guide videos than on gameplay videos. There is also less demand but often it's just getting some exposure that's helpful even if it's not hitting a home run on the first pitch.
If you look at a lot of small to medium channels' most popular videos I feel like they are often very specific content that people were able to search and find with that video showing up on the first page of search rankings for certain keywords that had demand.
It's also worth noting that even if you make a great video that you think people will find and love, sometimes it can take weeks or even months before that video catches on or the demand that you were expecting arrives. It's always important to keep innovating and not getting discouraged.
