Once you have trained your dog in the basic commands such as "sit", "stay" and "come", you need to make sure it behaves the right way around other humans.
You don't want a dog that jumps up to greet complete strangers, especially if you've been on a muddy walk! The best way to train your dog to greet people is with a polite sit down.
This is a game that will teach your dog to sit in front of a new person rather than try and jump up.
It will also often get a very positive response from other people, who will have great respect for your dogs training if you can get it to do this.
Like any training, it is best to do it when the dog is hungry so it is more willing to take the treats and rewards you will give to encourage good behaviour.
You'll need another person for this training, and while it is possible to use a family member, you might get better results in the long run if you use someone the dog isn't yet familiar with.
Start by walking towards the second person and getting your dog to sit.
When this happens, get the helper to reward the dog with the treat so that the dog learns they come from the other person and not yourself.
With practice on different people and patience, before long your dog should get the hand of it and learn to sit for new people even when they don't have treats.