Throw out your flash cards and grammar charts. Meet the Ancient Language Institute.
I know too many seminary graduates who have forgotten the Greek they learned in school, and since I'm planning on going to seminary, I am determined not to be one of them. I'm so glad I signed up to study with ALI. Instead of paradigms and flash cards, we have page turners and Greek conversations. If you can remember what it was like when you first learned to read, how you looked forward to finding out what happens next, then you'll have an idea of what it's like learning Koine with ALI.
My experience with ALI has been excellent. I've attained my current level of Latin proficiency much more quickly than when I was learning French, thanks to the ALI methodology. My two teachers, Luke Ranieri and Logan Kilpelä, have been excellent instructors as well - they add a level of insight that would have taken years to come to if I were only learning on my own.
If you want to come face-to-face with the great writers and thinkers of the ancient world, there is no replacement for reading them in the language they wrote and spoke. That is why I started ALI - to help students learn to read great writers like Moses, Plato, Caesar, and Ælfric in their original tongues. With ALI, you start reading on day one, and you'll be proficient before you know it.