The first thing, and a mistake I made with the young pup, is to be sure and not get suckered into the "so cute" thing in creating bad habits. Try to stay firm. Dogs easily forgive, and don't take criticism personally for very long.
I made the mistake of letting my pup go after fish I was bringing in on the river because it was just "so cute." Well, I'm still trying to break him of it!
If you just teach the simple commands of sit, stay, come, and heel; and enforce it enough so that they listen nearly EVERY time, it transfers to the river quite well. I also discourage rude habits like licking, approaching others, approaching other dogs, etc so that they don't become a threat to other anglers.
Teaching and training are just a matter of setting the rules, and being consistent. Repetition. I don't really know any tricks other than that. Keep commands basic and, again, consistent. Food treats are great bribery.
Maybe we'll have to try and get the pups together on a river somewhere this summer.