I am doing the best I can to develop practical fluency in Koine Greek on my own. I am focusing on reading - never translating - Greek. Lot's of it. New Testament, LXX, lot's of Apostolic Fathers. I am also working through some of Buth's materials, namely his Epictetus disc. I recently began incorporating a lot of audio readings into my routine, and I am slowly working through a Greek writing textbook. I'm desperately (desperately!) seeking locals here in Kansas City who are interested in developing this depth of skill in Koine as well, but so far I have not found a single person despite at least 2 major seminaries in town and innumerable and at least one legitimate classics program. It's been pretty frustrating.
Nevertheless, I share a lot of my experiences and methods (all of which are in their infancy, of course) at my blog greekingout.com. I post all of my reading aids (simple documents that cover rare vocabulary and syntax that trips me up) there, as well as some online readers for the Apostolic Fathers, although I am rethinking my stance on 'readers.' They should be great for those who are just dipping their first toe into the waters of the AF texts, but are probably too much of a crutch to aid in developing any kind of real fluency.
I would love to participate in an immersion workshop, but they are expensive and all very far away from my humble abode here in KC. Maybe someday they'll be taken on the road? Until then I'll keep doing what I'm doing and refining my approach. I've been enjoying the contributions of Daniel Streett, Randal Buth, Mark Lightman, et all to the process so keep it coming!