Hey Reanimator,
Perhaps here is the first or second serious reply to your reasonable question:
1. Start with a saw no bigger than 55 cc with an 18 inch bar. Your choice of brand. If you smoke a cheapie there is more than likely probable cause (you messed up) then you can move up the line with the added knowledge. For the first few months, cut timber no greater than 16-18 inches in diameter if possible.
2. Seek professional help starting out (not a shrink, a professional arborist). Maybe a dealer or a pro in your area. Maybe one of the expert yahoos in this group (despite their alleged sexual preferences they know their stuff) who resides locally to you could spend some time getting you started. If one obliges, have an abundant supply of a reasonable lager kept cold for the fee. As or me, I started alone at age sixteen. I am lucky to have the use of most of my limbs and organs (better the vision goes than the old joystick).
3. Spend the extra C-note and get GOOD PROFESSIONAL CHAINSAW SAFETY gear. Chaps, boots, helmet. Gloves? Pick a good name brand. Besides protecting yourself, you'll draw chicks since you'll look professional, and tough.
4. Don't invite your group of throttle happy redneck friends to cut with you when all they want to do is show off their saws and race to see how many trees they can fell simultaneously. Besides raping your timber, they will drink all the "reasonable" cold lager you had reserved for expert instruction. If you attempt to entertain pros from this group sans the requisite libations you will be sorry.
5. On the other hand....TRY NOT TO CUT ALONE. Bring along an observer at least. Ideally, (she) will be a fine scantily-clad knob-gobbler who will treat you to a delicious fried chicken dinner atop a red-and-white tablecloth after your (initial) work is done.
6. IF you are able to succeed in #5 above, please submit your story to the group so we can figure out how to do it too (the student...becomes the teacher). Be verbose and provide as many details as possible. A digital camera (and tripod) is a must in this business.
Regards, good luck, and happy holidays,
Dr. Hackemoff