Let's talk about jumping up on people.
First, let's consider the dog's point of view. If your dog does manage to keep four feet on the floor, they might not be noticed! They cannot express their excitement at your presence! In contrast, if they jump on you, they will get noticed, whether you appreciate that or not. Sometimes any attention is better than no attention at all, so let this be a generic piece of advice: train your eye (and your response) to notice what goes right with your dog rather than focusing on what goes wrong.
Communicating That You Prefer "Four on the Floor"
For example, if I were able to see a video of you with your dog, but the video was cropped in such a way that I could not see the dog, it should be obvious to me if your dog was cooperating with you – even if there were no sound on the video! If your dog has four feet on the floor, I should see a warm smile on your face, hands down low while you are bending forwards or kneeling (presumably patting and greeting your canine friend), and an interaction that continues for at least ten or fifteen seconds – minimum, so that I am convinced that your dog has been appropriately recognized.
In contrast, if your dog jumps up, I should see your hands held in a manner that access to your body is blocked. I should see you standing upright and slightly turned away. I should see a calm and non-engaging expression on your face. And if the dog is on a leash held by another person, I should notice that you are just slightly out of reach, calmly waiting, followed by deliberate movement towards the dog when four feet are on the ground to reward that good effort.
And what if your dog flips back and forth (a very likely scenario in the training phase) from paws up to paws down? Then I should see your behavior changing accordingly!
In addition to being noticed, your dog wants to get close to your face! That's because dogs know where are "personalities" come from, and it's not our bellybutton. Dogs jump up so they can directly greet your personality and tell you how much they have missed you!
With these things in mind, try to remember that your dog cares about you (in particular), and people (in general), which is likely why you got a dog. So while you might not appreciate your dog's style of greeting, don't forget that their heart is very much in the right place on this one. They love you lots! And your friends too!
Training Your Dog Not to Jump Up on People
Simply paying attention to what you like and ignoring what you don't like will work with a decent percentage of dogs; in particular the less energetic or calmer by nature dogs. On the other hand, if your 100 pound lab routinely body slams you into the wall, oblivious to your cries for mercy, keep reading. There's hope for you too because the process is the same for initial training as for "fixing." Just keep in mind that it will take a bit longer, and you may well see some regression at various times in the training process. Don't give up; it will work itself out eventually if you remain consistent.
The following video by Chirag Patel of Domesticated Manners is called "Four Feet on the Floor," and is an excellent approach to training all dogs of all ages and stages of "challenge."
Preventing Jumping Up with Smart Management
While you train your dog to show good manners with four feet on the floor, keep a handy assortment of management options at your disposal. For example, when you enter your house after an absence, keep a bag of small dog treats or cheerios outside your front door. As you enter, take a handful and scatter them on the floor so that your dog is torn between greeting you and scarfing up the cookies. Do not use this as an opportunity to sneak by and avoid greeting your dog at all – that's not nice! But do use it to take the edge off as you walk in. While your dog finds the cookies, talk nicely so he adapts to your being home and then greet him warmly but without becoming hysterical yourself.
If your dog is crated when you are away, then repeat the above scenario as your open the crate door.
This same method works quite well when you have guests. Throw down the cookies before you open the door, let your guest in, and ask your human friend to hold off on greeting your dog until he has finished the treats and is more calm and reasonable. It will also help to ask your guests to keep the greetings fairly low key to help the dog remain successful. Remind them that an enthusiastic greeting might be cute in an eight week old in the middle of summer, but it will be significantly less cute in two months when the puppy is three times larger and has muddy paws.
If your guest is not likely to help you with your training, possibly due to dislike, fear of dogs, or a fragile body, then simply put your dog away during their visit. People have rights too.
If the problem is a person who likes dogs just fine but who cannot reliably follow directions, and who insists on meeting your dog, then remove the puppy from the crate, attach a leash, and follow the directions from the above video. It's hard for even the most enthusiastic neighbor to undo your training if your puppy is on leash while you drop food on the floor. That approach keeps you on good terms with your friends and prevents your puppy from practicing behaviors that you won't want to see again.
When you're on a walk, do not allow your puppy to drag you up to people, because it's your responsibility to prevent your dog from being annoying. If your dog does molest an innocent bystander, don't be surprised if they do something unpleasant to your dog in self defense. That's on you. Mistakes happen; yes. But if your mistakes number more than a small handful, then maybe you aren't paying close enough attention. Fix that first!