How is King Arthur similar and different from Beowulf, Gilgamesh, and Achilles?

Okay so yes this is schoolwork, but I am not asking anyone to do the work for me. I just need some help getting started and knowing which hero would be better to compare to King Arthur in an essay. I am supposed to compare King Arthur to these heroes in terms of their deeds, their cultures, the values they represent, or any other similarities or differences I see in their stories. I have already written down all the similarities and differences I can think of, but I wanted to see if anyone else knows of any more so that I could make my essay longer and better. I would especially appreciate it if anyone could help with similarities and differences between King Arthur and Achilles, because I don't have as many for them. Easy ten points! Thanks for any help.