Buy a labelmaker!
Probably the best $20 I ever spent!
One of the best things I ever bought for the shop was an inexpensive personal labelmaker. I got this Brother PT-80 a couple years ago and use it all the time. Unfortunately, it's no longer available, but there are plenty of other similar ones.
This particular model is nice in that you can get various label colors, even clear. There are lot of options for the font size and you can even do two-line labels. There are also lots of symbols built in. The interface is a little quirky, but pretty easy to figure out.
The label comes out with a backing that must be removed. You stick the label into a slot on the printer, then fold it back and pull. The curling action separates the edge of the label from the backing, then you peel it off. Once you get the hang of it, it's simple. It helps, though, if your fingernails aren't trimmed all the way back.
Here's a few photos of stuff I use it on around the shop ...