If you can't think of an idea, check to see if there's a theme week going on. Besides the fun aspect, there's also the built in inspiration. Not sure what the theme is for the week, bookmark this page: https://imgflip.com/m/ThemeWeek.
Currently, it's Bob Ross week. I didn't think I'd be able to come up with an idea, but I've produced a few memes off of that. When you get to 20K points, the fun begins as you have 3 memes a day to post.