I love to hear good music at church and have even been known to sing in groups ranging from size 1-100. Here are some patterns I've seen a lot of lay choirs follow:
Bribe People to Come to Practice
There are a couple forms this generally takes: cookies or donuts. Which I prefer depends on the time of the day. Also freshness and quality matter.
Directors Love the Power Key Change
Don't know what the Power Key Change is? The song will suddenly shift a half step or so higher in pitch to a different key for much more dramatic effect. The Power Key Change happens when the director wants to really let you know that "Yes, we are really praising the Holy God, Mighty and Powerful". I guess the intent is to mirror His power by kicking the entire worship service up a notch (Yes, like Emeril. You just know the director is thinking "BAM!" in his head every time the key change happens).
Tenors Hate the Power Key Change
I've only met a few true tenors in lay choirs. Most 'tenors' aren't more than baritones who can sing harmony. Sheet music that directors like is written for true tenors. When the notes are already bordering on painful and then a power key change happens, I've seen a few 'tenors' collapse in agony.
Singing a Verse A Capella
Like the Power Key Change, singing a capella raises praise level (but without alienating your tenors). It can be a great ego boost for the choir - "Look how good we are, we don't even need a keyboard or organ cover our mistakes".
Singing in Unison
Choirs sing in unison to either show how unified in God they are, or because they really really really struggle being in harmony. Its either great or hurts. There is no middle ground.
Asking the Congregation to Join for a Verse
Most of the time it turns out awkward. They're never really sure when to join. What way does the director face? Does he look at the choir who is singing extra hard notes or the congregation who sing on autopilot?
What does you choir do?