If you're playing the same blues guitar chords over and over again during your 12 bar jam, maybe you should try something a bit different. This is just a quick article to give you an idea of what you can do to make things more interesting, both for you as a player, and for your listeners. As you learn to play better, these things will become natural.
Play Higher Up
Do you tend to play all your chords in the root position? It can get a bit muddy down there. Don't forget, you've got a bass player to fill in the lows. If you play the chords higher up the neck, it will just sound better in the mix. For this you'll need to learn you major and dominant 7th chords and barre chords. There's really only 2 shapes you tend to play barre chords in, the 'E' shape and the 'A' shape. (See below).
Don't play all the strings
What do you mean don't play them all? Well you don't have to. Often it's just as effective to play the top (thinnest) 3 or four strings using a movable pattern (see below). Pattern 1 is what you will probably recognize as a D7 shape. The root note (first note and name of the chord) is on the 4th string using the 1st finger. Pattern 2 is an A7 shape, the root note being on the 3rd string.
Play altered chords
An altered chord is just one with extra notes added in. The pattern below shows a dominant 9 chord, which is basically a dominant 7th with a 9th (or 2nd) added in. The root note is on the 5th string using the 2nd finger.
I always find that this one sounds best at the end of the 12 bar cycle, as the V chord (E9 if you're playing blues in A, at the 7t fret).
Hopefully you've found these tips useful. Give them a try and enjoy.
Keep on playing!