I am on season number two with my latest fishing bud (aussie shepherd) and feel as tho she has taught me quite a bit on this topic!
If I had any advice it would be to get him out on the water asap and as much as possible! It sounds like you have a very smart dog and he will learn what you want from him, it will just take practice and lots of it.
Being consistent is of the utmost importance, If you do not want your dog doing something or being a certain way then it will have to have "rules" from day one with no exception! (even if it is a cute puppy...) Let him get away with a few things here and there and he will always challenge you on it (ei. chasing wildlife). I like to spend as much time with mine in the mountains as possible, hiking has been huge for us... they like to be on the move and with all the river crossings and hill climbing she stays very close as to not be left behind. I hid from her a few times as a pup if she wandered farther then i liked, this worked wonders for us! Another good trick to do if you need to actually fish on your first few outings would be to tie the dog up right beside your bag close to where you are fishing. This not only lets you get a few casts in it also teaches them that they can get some rest and you will never leave your bag or them behind ( i wish mine would learn to get some rest when the bag was on the ground...) anyways let him cry if he wants... if you ignore it, it wont be long until he is offleash choosing to have a sit by the bag on his own.
With all that being said, everyday life is going to be far more important to having a good fishing buddy. Spending as much time with the dog as possible and building that connection is paramount. Whether it is playing in the back yard, fetch at the park, walks in the city or off leash on the river / in the mountains they will love you for it. With a high energy dog the best thing you can do is keep them tired/stimulated! If they are to tired they wont be bored and get into trouble, and if they don't get into trouble very much it is unlikely it will become a habit! Also never underestimate your dog (with consideration to breed) with four legs they can do twice the things your capable of in half the time! they can learn any thing you want them to it is just a matter of you finding a way to teach it !
First year is tough with maybe not as much fishing as you would like but trust me, BE PATIENT! it is so worth it to push through and bring him every time! Year two is going so much better and I cant wait for 3 4 5 6 7 8 ......