How to Conduct a Choir or "A Beginner's Guide to Waving Your Arms Intelligently"
Conducting is an art form and many people devote long years of study to perfecting it. This involves intense study of both the musical scores and how to create a physical gesture that conveys to the choir what you want from them. You may not have years to devote to improving your conducting, but you can always start somewhere, right? Remember that while there are many schools of thought on conducting, the idea is to wave your arms in such a way that your choir knows what you want them to do and when.
Basic Beat Patterns
The most basic instructions for conducting a beat pattern can be found in the back of an LDS hymnal. It demonstrates the basic gestures for 2/4, 3/4, 4/4, and 6/8. The LDS church also publishes a course on basic conducting and has an interactive conducting course on the church music web page.
For more instruction on basic conducting a good resource is: http://www.tetonmusic.com/conducting.htm This website has short instructional videos that demonstrate basic conducting gestures. You can also view these short videos on Youtube by searching for Michelle Willis. I don't necessarily conduct everything the way she does, but it is a good place to start with clear instructions.
Conducting Posture:
When conducting, I prefer to conduct in front of my torso/abdomen, fairly low, at elbow level. I feel that conducting fairly low and centered on your body (rather than up by your head or off to the side) encourages your choir to breathe low and supported from their abdomen. It also leaves your face more visible. The conductor should demonstrate the good, tall posture that he/she would like from the choir. I usually conduct with a flat hand and extended thumb (I know there are many schools of thought on this... I'm just giving my two cents). I think that when you do this your fingertips create a clean visible point for your choir to focus on. The single best thing you can do for your conducting is to watch yourself conduct in the mirror. Watch your posture and your gestures. Are you clearly communicating what you want the choir to do?
Preparation/Ictus/Rebound:
There are three parts to each beat in a conducting gesture: 1) Preparation, 2) Ictus, and 3) Rebound. The ictus is the point at which you change direction (the precise moment where the beat occurs, where the choir sings the note). The "preparation" is the swing going into the ictus. The "rebound" is the swing coming out of the ictus. The "rebound" is what tells you how to sing the music. For instance, a strong, snappy rebound would indicate that you sing something accented and marcato. A smooth and pulled rebound would indicate that you sing legato.
Cut-offs:
I do cut-offs differently than in the video above. I prefer to do cut-offs with a "slow-fast" motion within the beat pattern (kind of like a karate chop on the ictus). For instance, if I want the choir to cut off on beat "3", I conduct beats 1 and 2 normally. You slow the rebound coming out of beat 2 and then accelerate the preparation of beat 3 into the ictus. Continue with a quick rebound out of beat 3.
I know many people cut off with a "swirl and pinch" sort of gesture, but I personally dislike that gesture as I find it difficult to follow accurately and precisely (again, just my two cents). It seems like there is no way for the choir to predict where the "pinch" is going to happen and it is hard to see clearly. But again, the most important thing is to find a gesture that you can use to communicate clearly to your choir.
Basic Melding
When the choir is holding out a long note, rather than beating with equal emphasis on each beat, make the conducting gesture smaller until the cut-off. For instance, let's say you are conducting in 4/4 and holding the word "love" for 4 counts. On the downbeat of the measure the choir sings "love." After conducting a normal first beat, make the gesture smaller for the remaining three beats (basically just pulse the beat), then cut the choir off on beat "1."
6/8 vs. 2
One quick note: most pieces that are written in 6/8 time should actually be conducted in a slow 2 pattern. You feel three smaller sub-beats for each large beat: ONE-la-li, TWO-la-li. I rarely actually conduct in 6/8 (with 6 beats per measure)-- only if it is a very, very slow tempo.
Refining Your Conducting
Nothing is a substitute for learning from an experienced conductor. Many colleges and universities offer workshops or courses on basic conducting. Jill Winters taught a course on "Fundamentals of Choir Directing" at Brigham Young University. The lecture notes from this course are available for purchase from the BYU Bookstore or from her directly (contact her at jillw@byu.edu). I highly recommend them as they are a fabulous course of study for anyone looking to improve their conducting skills for an amateur choir.