Although some conducting teachers recommend a conducting in a box,beats on the sides will look distorted to people who aren't directly in front of the conductor. Thus they won't be able to tell exactly when the beat is. There should be a slight "bounce" at each of the dots on the line, so that the exact beginning of the beat is obvious.

CUES

To create a CUE, exagerate the beat before the beat that the music is supposed to begin on. Example: to begin 4/4 meter music on beat 1, conduct a vigorous--but in rhythm—beat 4, and breathe in as if you are going to sing along. To cue 4/4 meter music that starts on beat 4, breathe in on, and exagerate, a conducted beat 3. The conducted CUE BEAT should always be the correct motion for the beat before music should begin, and the cue beat should always be the same duration as any of the rest of the beats. 4/4 pattern is also used for 4/2, 4/8, and a fast 12/8.

3/4 pattern is also used for 3/2, 3/8, 3/16 and a fast 9/8.

Conducting patterns shown here are for the right hand (as seen by the conductor). Left handed conducting is an exact mirror image -- with the up-beat always coming from the side and the downbeat being directly in front of the conductor.

2/4 pattern is also used for fast 6/8 and cut time (2/2).

2/4 pattern comes straight down and bounces on the line for beat one, then circles out and bounces on the line again for beat two on it's way back up to the top of the downbeat.

2/4 pattern can also be a backwards J that bounces on the line for beat one and then bounces on the line again for beat two on it's way back up to the top of the downbeat. This is more difficult for the players/singers to follow than the McElheran technique but is in fairly wide use and might be easier to use in very fast music because it requires less hand and arm motion.

If the 6/8 rhythm is a fast one, it is often better to conduct it in 2 three-part beats--using the same conducting pattern as 2/4.

One may conduct with or without a baton; however closing the hand is a useful signal to indicate a change from open vowel to a hum.

References:
http://startachoir.99newsongs.com/id22.html