Let me repeat that, with feeling…
Do NOT buy a cheap pair of clippers!
You can get Wahls for $20 at Target or Kmart. I have the Color Pro, but the Home Pro dnooman mentioned is basically the same thing. Wahl makes the best product, IMHO, don’t mess around with anything else.
If you’re going for one length, you don’t really need a mirror, because you’ll probably want a friend to clean up your neck, anyway. Again, IMHO, a nice neckline is paramount to a professional looking home hair cut. After you cut your whole head, with passes in multiple directions (I usually go straight back, and 45 degrees offset), use your hand to feel for stragglers. Make sure and get your ears, also. This part’s easy. Just put the blade’s side against your head, and follow the natural curvature of your ear/hairline.
Finally, if you decide you want a blended look, it’s not much more difficult. You will want a hand held mirror (you can score one for $5, I’m sure) for this. Simply snap on the guard you want your sides to be (I use #2 if I’m doing it myself, #1 if one of my buddies is doing it for me), and go straight up, starting at your side burns. If you go straight up all around, it will give you a flat top look. Then use a guard half way between the guard you’re using on the sides, and the one you’re using on the top, to blend in the “edge” that you just created. Simple as pie.
Another technique is to “rock” the clippers when you get to the fade line, but I haven’t had as much success with this method. I’ve probably given 100 haircuts to my friends, and 100 to myself since I was 16 (I’m 25). I’ve paid for exactly two haircuts since then. Once before high school graduation, and once in Brazil before a wedding there.