Get the basics built in first, might seem boring but they're the foundations for the rest of your training. Sit and stays, make sure you always return to him while he's young - don't recall him. Practice recall when he's minding his own business just whistle him in with loads of encouragement. One thing I learnt from my first spaniel is if you want to take them in the beating line don't let them wander too far away from you when you're on a walk, need to keep them nice and close, they will always range out once they're on game. Make sure he sits while you throw the tennis ball, if he moves you