Respect is key, especially if you are over older people.
But that must be balanced with prayer, honesty and practice. One way to improve quality is to record the group and play it back - like with sports teams....
I am music director, composer/arranger, co-writer, and co-producer of a gospel group. I am the youngest musician and respect is one of the biggest factors. If you respect them, they respect you. You guys have to really do a lot as a band. Go out to eat, have fun together, go to concerts. The more the band bonds, the quicker it will "gel." Listen to some of you all's favorite bands together and get an idea of the overall sound that everyone wants.
Record yourself. When you listen to your recordings, take notes. Listen for how you can improve. When you get together with the band, discuss what you like about the recording, and discuss what can be improved - them and you.
The more time you practice together and work on your "sound," the closer you will get to that sound.