I found the jam to be the BEST way to improve. But…in my area there are not many jam options. There is the really beginner one, where everyone is sitting with a music stand in front them or the “pro” jam where everyone knows each other and there is no music and it is assumed you know all the songs. Neither is a good place to start…everyone is nice but its hard to get much out of either style. The beginners play so slowly and try to read (hence not listen) so it really hard to even chord along. The pros are overwhelming and you feel really dumb.
I my case, I started my own jam with a few friends…more like a band, we only worked on a few songs until we all got them. Its been a couple of years now and the group has grown and we actually can sound pretty good (one a good night with enough wine:). So I finally feel ready to try the pro jam …