Pray... for grace, humility, and discernment. Your job is to first stay encouraged yourself and then be an encourager to others. Assuming individual skill is not the concern, then the best way to play together as a band is to.... play together as a band. Extra rehearsals, coffee house or house shows can be avenues to pursue in the interest of "gelling." If the band members are willing, do Bible studies together so that you can grow as a community and not just musicians.
It is always difficult to be critical of another person's ministry; go check out other bands, secular and Christian, and be critical of what others are doing rather than be critical of yourselves. Unfortunately, there is no magic bullet. It will take time, but the investment should reap great dividends for you. Blessings and best wishes to you and your ministry!
"Rock On" (Matt 7:24-25)