I started out with pen, paper and cellotape ... all labels with an ID reference in the spreadsheet which contains the recipe. That's all you need when you start out.
After a while I wanted something that looked a bit smarter so I used Avery labels ... the A4 self-adhesive label sheets and template software ... to create my own design. I laser printed sheets of blanks and wrote on each label the flavour, VG/PG, strength and date it was mixed. Trouble with these paper labels is that they peel off easily and they're not juice proof even if you put cellotape over the top. They also don't register perfectly every time, ie the print doesn't line up with the pre-cut label.
So recently I took my design to a label printing company and had them print it on polyprop paper with permanent adhesive, all juice proof and perfectly registered. I still write on the details but now use a permanent pen. The labels never peel off until you want them to, then they come off in one piece without tearing or leaving an adhesive residue on the bottle.
It's not really a DIY solution, it's not particularly cheap either at £46 for 500 labels, but I like having a quality label on my bottles.