Here are a few practical tips that may help you be better prepared to minister to others on Sunday:
Prepare on Saturday. If you don't have time to prepare on Saturday, then consider cutting down your activities on Saturday night. Listen to some godly music as you set clothes out, find pairs of shoes, or do some meal preparations. Prepare your heart for the Lord's day just before you go to sleep Saturday night. Quiet your heart as you prayerfully consider the ministry He has for you the following morning.
Arrive at church early. Sunday morning may not be the best time to try to get some extra sleep! Save that for Sunday afternoon. When you arrive early you will have time to locate your choir folder and take care of any last minute preparations.
Meditate on the choir special throughout the week. Post the words somewhere you will be often throughout the week, or keep them on a note card in your pocket. Your heart will be more focused on the ministry of the choir when you have taken the time to internalize the message of the song. This will also help you "keep your nose out of your book!"
Be right with the Lord. All the physical preparations in the world will not prepare you to minister if you are not prepared spiritually. Let your ministry on Sunday be an overflow of your walk with the Lord through the week!