What angle should I give to my drafting table?

Maybe it's a silly question, but I can't find information about it!

Is there a right position to draw correctly the perspective and the proportions or is it up to me?

Please, give me some advices! Tell me what you do!

/Suzy

At least a 45 degree angle is the common usage position for drawing. I'm not sure what my drafting table is set at, I just adjust it to what is comfortable for me. I must measure the angle when I get a chance just out of curiosity.