well i dont really draw anymore....but when i did i usually took about 3-6 hours on my good drawings...mechanical pencil is your friend....lol...um invest in some high quality erasers such as Staedtler. the easiest way to get proportions down is to find some pictures of cars in magazines and just copy the lines (not trace) i mean like look at the lines and draw them exactly how you see them with regard to spacing and length. if u can do this then your finished product will be nicely proportioned and soon enough you will be able to draw it without a guide photo. i would include some of mine but i think i deleted them..