Watch the Stella by Starlight online guitar lesson by Mimi Fox from Jazz Performance
First step is to memorize the changes completely! Here's how I do it: Learn 4 measures at a time and memorize according to chordal function/key such as: "Two, five, one in Bb Major", or "Two, five to the four chord" etc. Pretty soon you will have strung together 8 measures, than 12, than an entire section, and finally the entire song. Remember to hum the melody or sing the lyrics in your head as you are playing the chords so you reinforce the song even more.