If you wear bangs or a fringe, you'll find that you'll need to trim them fairly often. Many hair salons will trim your bangs for free between regular cuts. However, if you're growing out your hair, you may not be going to a salon regularly anymore.
If you already have straight-across bangs, here are some tips for trimming your bangs yourself.
You don't need much in the way of supplies for this. A mirror, clips or a headband, scissors (preferably barber's shears) and a fine tooth comb are the only tools you need
First of all, make sure your hair is dry when you trim. Wet hair will shrink as it dries, and your bangs may well end up being too short.
Now, clip all hair back, leaving only your bangs exposed. Comb them straight down with a fine-toothed comb.
With the fingers of your dominant hand, pinch the bangs together and place them right at the bridge of your nose below the brow line.
Take your non-dominant hand and grasp the bangs horizontally against your forehead between the index and middle finger. This frees your dominant hand to hold the scissors. Slide your fingers down to the length you want your bangs to be. Make sure that your fingers are truly horizontal and not tilting to one side or the other. The fingers will serve as your guideline. However short you think you want your bangs to be, lower your fingers by about 1/4 of an inch, to prevent accidentally cutting too much off. You can always trim more later.
Now take your scissors. Hold the scissors almost vertically and make repeated vertical snips until your bangs are at your finger line (the guideline).
Comb bangs straight down with your fine-toothed comb. Look for any errant hairs that may have escaped your scissors during the trim and snip them off.
Now, check the length. If you're happy with the new length, you're done. If you need a bit more cut off, repeat the process with a slightly higher guideline.
You're done! You've cut your own bangs. With the almost-vertical cutting method you'll not have the straight as an edge home-made look, and by having pulled the hair to the center of your forehead, to the bridge of your nose, you'll have a nice natural line.
For those of you more visually oriented, I'll make a video the next time I trim.
I'll give instructions for cutting bangs for the first time in a future entry.
Remember cut less to start with. You can always cut more. Good luck!