I have hired a personal trainer for my 18 month old male Maltese. He came and worked with us for an hour one day and then offered to take the fee of that hour off for a week (5 days) of training at his facility. I agreed. And I am very happy to say that we have one more day of training (unless we decide to go for another week) and Puppy Dog is doing so much better!
The main thing is to teach your puppy some command that will make him stop whatever he is doing, like "Sit!" Then reward him for that and give him a treat and praise him! Anytime he/she is doing something unacceptable issue the command in a strong voice (I have to stand up and point my finger at my baby in order for it to take full effect). Then, reward with a treat and work with him/her a few minutes, luring them into a sit, sit up, lay down with treats. After a while they will "get it". Try not to freak out (as I certainly did on many occasions!), and just stay calm and keep treats on hand.
Good luck! :)