Google operant conditioning and study it. In summary Operant Conditioning is about rewarding the dog for its good behaviours.
If your puppy is naughty smack yourself, never smack a dog. You smack yourself because you have not trained the dog properly and the dog needs to learn it has done something wrong by seeing you get punished. Dogs have a fight / flight response and the more this is trained by punishing a dog the worse that dog will get and eventually it will become unfriendly, unmanageable and a fear biter. A punished dog will never be your best friend.
When a dog is naughty smack yourself and make a good noise and growl, then place distance between yourself and your dog. Simply taking the dog outside and leaving it outside for a while and definitely at least two minutes after it has ceased complaining about being outside.
Dogs are a pack animal and will seek to be pack leader. If you allow the dog to believe it is the boss it will demonstrate this by the mounting behaviours. Dogs need to be cared for with loving CONTROL. Show it you are the boss by never letting it bully you. If you want the dog to stop doing something or you want to pick up your dog then pick your dog up, do not let it squirm and escape. You are the boss, not the dog.
Research has shown that animals will eat till their protein needs are satisfied. If the dog gets a low protein diet it will over eat and become morbidly obese. If your dog is fat feed it 24/7 with dried puppy food with water handy, puppy food is generally 26% protein. Dogs get their minerals from eating bone, we get ours from eating vegetables. If the poo is a dark blackish it can be a good assumption the diet is low in minerals and your dog could eventually suffer. The simplest remedy to minerals is to add garden lime to mince.
Flea treatments supplied by Veterinarians and pet shops for dogs are enormously expensive. You can purchase $60,000 worth of dog flea treatment for $155 if you buy the same thing meant for horses. Coopers Easy-Dose pour on for cattle lice and fly treatment has the same ingredient as in Advantage and 1 litre will make 3 litres of advantage equivalent with the addition of 2 litres of water. For a normal adult dog standard size 2 ml every month will keep the fleas at bay. When it comes to worming be a little more careful.