If you won't want your dog to jump up on people when he's bigger, don't let him do it as a little puppy. A small dog that jumps up can be a big problem for children, and a major annoyance for adults. A medium or large dog that jumps up is downright dangerous.
Never knee a puppy in the chest, kick him, or step on him in an attempt to keep him from jumping on you. If you don't connect, your pup will probably see your maneuvers as a fun game. If you do connect, you could severely injure your puppy. Teach him that jumping up doesn't get him what he wants, but that calm, polite behavior does.
When your puppy jumps up on you, he wants attention. If you touch him, push him down, yell at him, or otherwise interact with him, he gets what he wants. If you ignore your puppy's antics, though, he'll soon figure out that jumping up doesn't get him what he wants at all.
Many puppies will stop the jumping nonsense very quickly if you fold your arms, look up at the sky, and completely ignore the behavior. If you do this, you need to do it consistently and never respond to the puppy any other way while he's jumping. Then as soon as he gets off you and has all four feet on the ground, quietly tell him he's a good puppy and pet him gently. Stay low key—the last thing you want to do with a pup that likes to jump up is get him excited again. If he does react to your attention by jumping up again, ignore him until he stops.
If you use this method, you need to be sure that while he's learning not to jump, you never put yourself within reach of your puppy unless you're willing to be jumped on. He won't know the difference between your grubby puppy clothes and your work clothes, so don't go near him unless you're wearing puppy duds until you're confident that he won't jump on you. If that means you have to get up a little earlier, do your puppy duties, and then crate him before you get dressed for work, so be it. Same thing when you come home—go change before you let the puppy out. If you stick to this regimen, your puppy will learn not to jump. But if sometimes you ignore him, and sometimes you react by pushing him off, hollering, and otherwise getting all excited, he'll figure that sometimes jumping starts a good game and he might as well give it a try!