How do you come up with idea's for video series?

I am struggling at the moment to come up with video idea's for my channel, I have a gaming channel so it should be relatively easy to make content... you would think.

If I just upload gameplay to the channel what is there to distinguish me from every other gamer on YouTube?

I'm trying to come up with something unique.

I just figure out something to talk about and go for it! Recently I actually did a tutorial video on installing a video card! And I have another coming up in a few days. It is refreshing doing something else than the status quo.
Try to make a brain storming to come up with unique idea and using imagination is very important.
You could think about what most gamer are looking for and how to attract them. you can even go deeply into sub-specialization. For example, keep post Tech-News videos pertaining to Gaming industry and so on.

At the end, you should do what you like to do and so your choice should based in that.
I either write up a script for film, or ponder ideas, for my gaming channel I take in consideration of what my audience wants to see as well as what I LOVE to play! :) You should always make content you enjoy, and not just content you feel will become popular in my opinion :)