Things you know about. Things that you've observed and find funny. Know any good jokes or puns. Good insults. Funny things in the news. Personally, I stay away from political memes, many users on this site have are passionate about their political views.
I've been lucky on the site and have over two million points. Tap or click on my user name, view some of my submissions and see if any inspire you. Repost one. I don't care. Hope I've helped.