Singers are vocal athletes.
Just as an Olympic athlete would not compete without doing some dynamic stretching and warming up, you need to warm up your voice before singing.
Take Care of Your Body, It’s Your Instrument
Learn how to keep your voice healthy.
Exercise regularly. Make sure you are sleeping enough.
When practicing, periodically stop and ask yourself “how do I feel?” Take a break if you need one.
If when you are singing your larynx seems to scratch or tickle – Stop. You may be getting a cold or worse you are constricting the throat. Singing while constricted can damage the voice. Learn how to retract the false vocal folds. If you are sick try to rest your voice..
Can you hear yourself over the band? No? Stand well away from the drums. Turn down the amps and/or turn up the monitors. Playing too loud is an amateurs mistake.
Try not to eat heavy greasy meals before performing.
Avoid constantly clearing your throat. The habit of clearing the throat is a vicious circle. When you clear your throat (or cough) you are banging the vocal folds together. This irritates them and makes you want to clear your throat more and round and round you go.
Stay hydrated. The best thing to drink is near room temperature water. Alcohol and coffee can dehydrate you. Teas with honey etc may soothe the throat but they don’t touch the vocal chords since they are closed when you swallow.