Playing in a group is completely different than playing by yourself- it's harder to hear yourself, the tempo is dictated by the drummer, and so many other issues. Here's some simple ways to get better at playing in a group (and hopefully get you that call back).
This is a mantra that applies to every aspect of playing in a group- the simpler, the better. Simplify your playing, your gear setup, your notes. Allow yourself the maximum time to be present and aware of what's going on around you. Most groups don't need a virtuoso- they need a musician that knows how to tastefully fit into the group.
2. Be others centered
Everybody loves an others centered person, both on and off stage. Make a point to memorize the names of those around you in the group (I write them down), and listen carefully to the other members of the group during performance.
I'm constantly amazed at how musicians will be so zoned into their own instrument, that they'll completely run over the other musicians in the band. (As a side note, if your a keyboardist, pay special attention to the guitarist. You occupy the same sonic space as him, making it easier to run over his playing. )
3. Do the little things
As a band leader, I'd rather hire a good musician that's easy to work with, shows up on time every time, offers to help load in gear, and is conscientious about his appearance and gear, than a great musician that doesn't do any of those things. Talent is important, but being easy to work with is essential.