I didn't read all the replies here, but I have a white Boxer who is 5. We had 2 Boxers when I was growing up, and then I fostered a pair for 4 months the year before I got my dog. Learn from my mistakes!
-When you socialize with other dogs, make sure it's not just play time. We would have dog play dates with other puppies, and my dog now thinks that any time she gets together with another dog it's time to go beserk and play. It's so, SO irritating. She cannot leave the dogs alone and exhausts herself. We can't take her to family events if there is another dog because she obsesses over them.
-Recognize that Boxers play differently to other breeds. For this reason I reluctantly did not renew her dog park membership. It was getting to be too much - labradors snapping at her when she tried to box them, small dog owners getting upset when she pounced (with all good intentions) on their dogs and got slobber all over them... Her best friend is another Boxer and she plays very well with him.
-Be really careful to watch out for Bloat. My dog bloated when she was 2, even though she was on a raw diet. I was very lucky that she didn't torsion.
-Don't even bother with clicker training. I did this when she was small and it was a MASSIVE waste of time. I think only the most dedicated, 100% focused Boxer owner can make clicker training work. I've found positive repitition and praise worked best for her. She did great in group classes, but out in the real world she sucks on the leash. Make sure you don't let up on leash behavior for the first 3 years. If I had been more proactive, she'd be better. As it is, I have about 4 types of harness, head collar, martingale collar, Halti, Sporn etc. etc. and none of them help with her pulling.
-Because we raw fed our dog, she got used to being fed by hand and she is the most gentle dog around food. She was also trained to wait before eating anything (we say "take it!") which has been helpful with a toddler to stop her eating unsafe things off the floor like raisins.
-We taught the wait/stay/release commands and these have been great when taking her in and out of the car.
-Don't underestimate how bored Boxers get. They love to go out and see people/stuff. My dog is happier if I just take her out in the car on an errand, than if she gets left at home. Back in England, my Mum used to walk our Boxers 3 times a day for a total of 2.5 hours. I just can't achieve that, but in nice weather I aim for 4 hour long walks a week, and it makes her SO much happier.
-Watch out for the sunbathing, they can get burnt noses!
Enjoy your puppy!