Watch your dogs body language. The Pup will tell you alot.
Is he confused?
Does he get it?
Is he going to break?
Is he going to try to blow you off?
Has he had enough?
Short successfull training sessions make a confident dog.
If you are hitting a wall, go back a few training sessions and do something that your pup understands and does. End on a good note. Then try again in a 2 or 3 days later and the light will usually come on.
Make sure you go to the bathroom before you go afield. No sense in hurrying things.
The best part of training is seeing the light come on in your little prot'eg'e.