Dude, this is basic marketing. Go read some find-a-niche guides, or just do this:
Go to amazon and find a product to promote. That can be anything from kids wear to hunting books whatever.
Go to google keyword tool and check out the competition. If the niche is not too competitive go for it.
Go to clickbank or whatever service you're getting profit from and find products related to your niche.
Make your video or site promoting those products.