My puppy has learned sit, down, and rollover. What should be next?

there are always lots of things you can teach dogs. for one thing my family has thought my dog so many trick he now started to mimic or motions its quite funny. there are tricks like fetching mail. my dog goes out with us when we check the mail and brings it back to a certain person that we tell him to bring it to. dogs enjoy doing things that give them praise so pretty much any thing you want to teach him it will be fine. when you asked them to do tricks they get excited and try to please you as much as they can. so teach him what ever you want just give him lots of praise :)