Are you thinking of a one-on-one situation or a class of 4-8 students?
Make up a nice finished sample so people know what to expect. Print up a supply list with a schedule on it.
Be sure to draft all your own patterns and handouts (accurately!) OR teach from a commercial pattern and make sure every single student has her own purchased copy of that pattern.
Remember that you can run 100 sewing machines but only ONE iron on most electrical circuits. ;) If you are doing rotary cutting, you will need a lot of table space. Try to organize cutting and sewing so that they don't have to have their mats AND their sewing machines on the table at the same time. (For example, when they come to the first class, tell them to set up the mats but leave the machines on the floor for now.)
If you have more than two students, have them initial all of their tools with a Sharpie marker when they arrive.
Good lighting really helps!
Wear lipstick (seriously, Pepper Cory taught us this in a "how to teach quiltmaking" class I took from her) because it helps people read your lips while you talk. Make sure people take breaks if they look stressed.
I could come up with a hundred rules and ideas for you... but mostly, remember that even though this may be a job for you, it's just a fun hobby for most people. If they aren't having fun with it, they might as well go buy a quilt at JC Penney. Keep it fun.