I just ordered a Wahl self-haircut clipper kit.  I have a standard
male haircut with relatively close shaved sides (clipper size 2 or
1A??) and a short-medium length parted top.  Nothing fancy.

The only reason I get a haircut every month is because the sides of my
hair become too long, start to "pop out" horizontally, and begin to
cover my ears.  The top is fine.

I would like to use this kit to just shave the sides and leave the top
alone.  The problem is that, if I shave the sides, I'd have to keep the
lower back area the same length or else it may look unusual.

What is the best way to clip the sides and back *by myself* and not
make horrible errors (i.e., over- or under-shave one area)?

Lol I actually cut my own hair. I am very paticular who cuts it. As
such i use the link method i now the correct link and use scissors.
And for the back I use a mirrior. Believe it or not I have it down to
perfection. Although I must say i bought a hair trimmer a few months
back and as seeing as I keep my hair short it works perfect. I bought
it at target and it has different link plastics adjustments. And it
works great.

Hi David.  Thank you for your comment.

What is the "link method"?

Also, about the mirror for the back, do you use a stationary mirror or
do you hold one with your free hand?

Thanks again!

I from experiance know what link to cut it. I pull it out with a comb
much like your hairdresser would and clip the hair that is to long.
Same thing just do it yourself. And as for a mirrior I have used a
seperate hand held mirrior to peform such a task. But in my bathroom i
have a trifold mirror and just open the other two and leave the middle
one in. This give you the best reuslts when inspecting it exspecially.
You just have to have some patiance and a steady hand. It takes me
about 15minutes to perfectly cut my hair the way I like it. The barber
shop kept cutting way to off from the way I like it so I had to take
matters in my own hands. The best advice I can give you is don't cut
alot your first few times that way if you mess up it will be fixable.
Better to mess up and have it to long than to short.