I will sing praise to your name, O Most High.
Here are some basic, practical suggestions intended to help you sing for the Lord as a worship leader. Whether you are leading in a kinship setting or on Sundays, your voice is your most important instrument, and it is worth taking care of and using wisely.
First, be audible. If they can't hear you, they'll sing softly or not at all. (An uncertain trumpet produces uncertainty in the troops, 1 Co 14:8.) Stay close to the mike if you are using one. If not, then keep an even tone as best you can, and be clearly audible. Notice I did not say to be as loud as you can; more about that later. If you have a hard time being clearly audible, reading the resonance section in the article on voice training may help you.
Remember to inhale. This sounds silly, but often we are so focused on chord changes, and which verse to sing next, that breathing becomes our lowest priority. If you notice yourself running out of air before the end of a phrase, or singing weakly, you may conclude that you need to push harder with your stomach muscles. I don't think that's the answer; I think you need to suck in more air before you begin each phrase. Keep a big lungful available, a spare storage supply, so that you're never on that last gasp.
Keep a glass of water handy if you need to, or cough drops if you like them. Singing with a dry throat can hurt your voice.
Singing full power too often or for too long at a time can strain your voice. Sing clearly; if you must, sing fairly loudly, but don't make a normal practice of singing full power. Why not full power? A couple of reasons.
First, there are a few moments in a worship service where full power from one person is appropriate-- like when you are prophesying a new song, for instance-- but those moments are unusual; and you want those moments to stand out. In general, save the full-power stuff for the right time and place.
Second, singing full power is a good way to hurt yourself. Just like any other muscle, overwork can damage your vocal cords. Exercise moderation. Although you've collected a good lungful of air, you don't want to force it past your vocal cords. Carefully release enough air to get a good even tone. (Try singing in front of a candle-- does the flame flutter a lot? That same forcefulness is also hard on your vocal cords. Try and minimize your P's and T's so that it flutters less; sing gently, carefully, clearly.)
Third, singing loudly puts you and your voice under pressure. One of the worst band-related mistakes I ever made-- for months at a time-- was singing at full power for the sound man. (I like to sing loudly, don't you? It's fun.) But the sound man had to balance the voices, so he turned me way down; and then to be heard I had to push hard. And I stupidly let it stay that way. I strained my voice week after week by singing at full power. For a long time after that, singing was physically painful. Not good; not a clever investment of the gift God entrusted to me. I had to sing very very softly for a long time before it stopped hurting again.
Don't strain your voice; train it. Learn how to get the most out of it without hurting it. Take care of your voice and be a good steward so that you can sing whenever God wants you to for as long as he wants you to. And to do that you may have to sing gently.
More pitfalls to avoid: a couple of pet peeves and common problems.
1. It is common for experienced women singers to sing slightly flat. Why? Too relaxed I guess. Breathe deeply, focus on projecting the sound up... most of all listen carefully to yourself and the other singers and make sure you're not sliding into flatness.
2. It is also common for very experienced singers, both male and female, to get so relaxed that their vibrato gets out of control. You know, the opera singer syndrome. In the church, I have heard veteran singers with such extreme vibrato that the congregation couldn't follow them, and followed the backup singers instead. What's the use? Again, breathe deeply, listen to the sound, tighten it up a little. I don't think vibrato should ever get beyond a full step, but it happens all the time. Listen to a tape of yourself every so often and see how you are doing. Trust me-- NOBODY will be honest enough to tell an experienced singer that their vibrato is getting sour.