A have another question about my pup.....How do I get him more interested in play/games such as chasing a ball? He is about 3.5 months, and he often doesn't want to run after stuff (ie tennis ball, kong, squeaker). Or he will run after it 2-3 times and then he is done. Then sometimes he will start playing on his own.

I'd like to get him to enjoy fetch type games since it is good exercise for him, just not sure how to go about it? Any suggestions for other games?

What am I doing wrong?

Thanks!

I learned some things to do from watching Ed's video Building Drive and Focus. Also, I got some ideas from watching the video of Cindy teaching one of her dogs to retrieve. I think it is called shaping. Marker training makes the process go faster. Watch your dog for behaviors that you want and mark and reward them. Start with simply looking at the object and mark that then work to going to object, then touching object and on and on. Take your time, be patient.
Finally, it is important to remember to quit before your dog is ready to quit. At this age that is 2-3 times. I know you are not ready to quit but from the puppy's point of view, he is bored and ready to do something else. You don't want to get to this point. You want to keep him wanting more.
My 4 month puppy would rather chew on sticks that run after balls and I have a yard full of tress and sticks. However, if I play with the ball by throwing it up in the air and cathcing it and acitng like I am having the best time in the world, suddenly he's interested. Then I do 1-2 throws giving him great praise for suiing to the ball and even greater praise when he brings it to me. I don't touch the ball but we have progressed to where I trade the toy for a treat occasionally. After 2 throws I walk off. I end play so that it reamains mine under my rules. Then I just walk around and enjoy just being in the yard with him. After a while he gets distracted and I find a place to hide. Then I call him to me and he comes running. WHen he finds me I give him big, happy praise. This reinforces recall.
I also take him to playgrounds and let him climb all over the equipment.
I play tug games...again, Ed's video discusses this. Finally, mixed in with fetch and hide and seek and tug I will throw in a couple of sits or downs. I mix it up and keep sessions very short and I don't repeat the session to soon...I think this info is in the Obedience video and maybe in some of the written stuff, too. Ed even gives times to wait between sessions.
There is a lot of good stuff in those videos.
Another thing that popped into my head is that with puppies, you want to be careful not to overexercise them, yet another eason to keep sessions short.