Watch the Pack of Lies online guitar lesson by Mimi Fox from Jazz Performance
Practice trading lines with your fellow musicians as much as you can as it's not only good for your musical palette, its fun! I think it's also important to listen to recordings of your favorite players doing this. Also, try and go to live music performances where you can see/hear musicians doing this in real time. It's all about communication and trying to share a musical story with your fellow musicians.