Haha, funny question, seems like common sense. But, I suppose there aren't any stupid questions. If you're with a group of people and you're up to snort a line act like you've done it a hundred times, like it's no big deal.
Make two neat little lines as quickly as possible on a clean table, or on whatever surface you'll be taking them on (car dash, toilet lid, top of your hand, your friends back). It's always fun to make your lines on a mirror, or on a black marble table top. Do this with a card from a deck of playing cards, or your credit card or something of this nature. Make them about as thick as a straw, and as long as a pen lid, or whatever you can handle or want I guess... Tightly role up a 20 dollar bill (you can use whatever you want, or any bill if you're not from america) You can also use a straw, or a rolled up piece of paper. 20's are my favorite, I have no idea why. On a show in MTV it showed that it is true that some 20 dollar bills have trace amounts of cocaine on them, hmm.
Hold one nostril closed with your finger, and as you put your head down to the table where the coke is, put one end of the 20 just up to your other nostril. Don't shove the bill up your nose as far as it will go, just as close to your nose that you can, so that you can suck in the white real good. Put the other end of the bill down slightly above one of the lines, and breathe in like you're sniffing when you have a cold. Slide the bill across the line snorting the whole time until it is all up your nose. Breathe out your mouth afterwards, careful to not blow the other line off the table. Now sniff rather hard to get the power all the way up into your nose. immediately repeat the other line using your other nostril, then sniff hard again. Using your card, clean up any left over powder by sliding it on the table making one last tiny line, and suck it in the first nostril that you used.
Afterwards sit back and relax. You'll feel numb, and begin to feel the drip in a minute. Check your nose in the mirror to make sure you don't have coke nose in front of your relatives or friends that aren't open minded.