1. Clean and chop up whatever plant material you are using (the amount of plant material you'll need depends on the size of your jar(s). If using berries, they don't need to be chopped. Fill up your jar(s) with your chopped herbs/plants. If you are using fresh plants, you should pack the jar(s) full (squish as much plant material as you can in there); if using berries or dried plants, just fill your jar half way.
2. Pour in your vinegar, cap your jar, and let steep for 2-8 weeks in a dark cabinet (if using fresh fruit, 2 weeks is enough; the other plants can sit for 6-8 weeks). Check your vinegar every few days and see if the vinegar is getting low- add some to cover the plant material if needed.
3. When the recommended time has passed, strain out the plants (or eat them!) and label your vinegar so you know what you used to make it (honestly this is a good idea- don't rely on your memory. If you are anything like me, months from now you'll stare at all of your different bottles and you'll have no idea what's in them!). Put your vinegar(s) into pretty jar(s) if you are giving as a gift and are so inclined.
4. Put the date on your label too so you'll know when it's no longer good. These keep for 1-2 years, but after that you should probably make a fresh batch.