I have some tips for you!
When you start to train your puppy, (I just went through it a month ago) make sure that you don't feed him before you put him in his crate. Also the vet gave us the tip to go out with him every time he has to go.

We trained our puppy, Prince, to ring bells that we hang on out door, and he does it so well, and he is only 3 months! What we did is that every time we took him out we shook the bells. He caught on quickly.
Good Luck