So you want to look cool jamming?
The Compleat Idiot's Guide To Teach Yourself 'All Blues' in 24 Hours For Dummies In A Nutshell
G G G G G G G G G G G G C7 C7 C7 C7
Left hand: If you want to play bass and you're allowed to do so by your bass player, follow the distinctive bass line you can hear on the record ("Kind of Blue"). For the G chord, it's |:g-D-E-D-F-D-E-D:|, for the C chord, it's |:c-G-A-G-Bb-G-A-G:|. Otherwise, try to do something imaginative with your left hand such as simply extending the stuff you will play with the right hand.
Right hand: Several possibilities here. The trademark trill that can be heard on the record consists of G and A/B. Hit G, then A and B together and then again G. Do it softly, and if you want to impress people, use your left 2 finger for the G and your right 2 and 3 finger for the A/B combination. Jazz pianists love to do this on TV. Oh, and that was for G. For C, you replace the A by a Bb and the B by a C.
On the record, you can hear a certain riff, which is just a tierce shifted around. For the G chord, this is b/D - C/E - D/F. For C, it's the same with bb instead of b. Now you play piano, so you can play more than just two notes. Add two tierces to that b/D combination and you get a nice jazzy chord: e/g/b/D. Shift this entire chord like you shifted the tierces before. You can add the tierces on top of the riff instead of on the bottom if you like so. Just find out what sounds the jazziest. Try adding even more tierces by using both hands together to make monster chords. Go easy on the volume, though -- no more than mezzoforte, or people won't hear the rest of the band.
Now take the riffy stuff, vary it metrically and move it around the octaves. Experiment. Rapidly, it'll sound a lot like the comping on the record. I kid you not. With two hands and three possible occupations for each (bass, trill, riff) you can do a lot of combinations, too.
If you want to play the theme, go ahead and play along with the record(*) until you've got it down pat. I don't play the theme 'cos I play in a combo. The vibes play the theme. I'm just playing chords and looking stupid.
D D Eb Daug
For this, hit the chords. D is D-F#-A. Shift everything up one key for Eb, then shift everything down one key except for the Bb and you'll come out with Daug.
Solos: Do what the hell you want, listen to the record a lot before practising. Basically try the C and G pentatonic scales and all the notes and chords you've been hitting on for the riffy stuff.
Feel: Just listen to your drummer. He/she may change the feel without notice, since it's so darn easy with this song -- you can go from 6/8 feel to 3/4 feel, 4/4 feel, 12/8 feel, everything. It's fun to do if everybody notices. For the original feel, again: listen to that record. If you play it much slower, keep it shorter or the melancholy will become unbearable to your audience.
(*) If you can play along with it. The first version of the record to be in the correct pitch for playing along is the remastered 1997 CD.