"Teach" is a big word, I can tell you how I did ;-)
I first started by tracing a line with a pencil on the side delimiting the natural binding (in my case 7mm). This is a very important line because it defines the level you have to reach by removing the material. It's also very impotant that you, using the chisel, leave 1mm from that line: you will trim it with sand paper later in the carving process.
Then I traced, on the top, the "flat zone".
Here is a picture where you can see the rough curving with the chisel and you can also see the line I traced to delimit the "flat zone":
Picture 1
You have to remove the wood in excess without going too near to the limit you traced (1mm). When you have reached a sufficient level of rough curving use the sand paper (I started with a 80) to complete the curving removing the famous 1mm of tollerance you left. I decided to do all by hand because if you use a sanding machine you don't have the sufficient control as you do it by hand.
At the end, it is important that you remove all the sanding erregularities carefully: when you have a glossy surface you will notice all them as a kick in the stomac. To do this I used a tangental strong light source to identify all the points to be sanded.
I hope my explanation will help you.
There are also other techniques.
Picture 2
Picture 3
Picture 4
that really helped! thx, capu! but one more question, when you carved the body (between the edges and flat zone) using a chisel, did u carve it flat (not curved) first and then contuored it (to make it curved) with sandpaper or what?