Hi Christopher. Here's two good threads on the topic:

* http://www.weplay.com/questions/480-What-are-some-good-ways-to-build-arm-strength-for-baseball

* http://www.weplay.com/questions/342-I-am-a-LL-pitcher-How-do-I-strenghten-my-pitching-arm

Hope it helps. T.J.

play catch...lots of it

Hi Christopher, The very 1st thing I can tell you is Warm up and Stretch. You hate to hear it,may think it's Bogus,but do it. I don't know how old you are,but take it from me,I've had 2 surgeries on my left shoulder. Don't do alot of push-ups,then go out and throw 80 balls. I've seen that to many times. Everyone says long throws,but try using weighted training balls. You can get them at many sporting goods stores. Just remember,the higher weight of the ball,the less distance/throws you do. Also it is important you use good form. Remember,warm-up-stretch,it helps prevent injuries. Again I don't know your age,but since your an outfielder,maybe you could run steps some where also. Outfield speed is just as important as an arm. Warm-up,stretch,don't over do it.
Mike.

Keep throwing, my friend. And focus on developing good, fundamentally sound throwing mechanics. Then once you've built a mechanically sound foundation, you can add exercises like Jobes and Throwers 10, and you'll be on your way to having a strong and helthy arm. Keep working hard!

Best,

Steven Ellis
Former Chicago Cubs pitching pro
http://www.thecompletepitcher.com

play long toss whenever you can cause that helps alot. i do a lot of drills that deal with the core of the body. trainers and my coaches always tell me to work the core because if you use your whole body your arm is stronger and more accurate. i pitch and i dont if this will benifit you but me and the team i play on work on our core a lot. its helped everybody on the team infielders and outfielders. give it a try