You've probably heard about DIY e-liquids and flavor concentrates by now, but it was always something that seemed way too complicated to try at home, especially for a beginner. Well, I'm here to tell you that it's not such a difficult process and with a little practice it could help you save on hundreds of dollars on the long run. When I'm not sampling the dozens of e-juices I get in my mailbox I constantly experiment with various DIY recipes and try to add new and improved flavors to my personal collection.
Understanding flavor, base and nicotine
The first thing you need to understand about DIY e-liquids is that it's a process that consists of three parts. First part involves strictly the flavor side of your e-liquid, the second involves the base and the third involves the nicotine. Also you need to understand that there are two types of flavor concentrates on the market – the ones that have already been mixed and are ready to be vaped once combined with a base, and the ones that are just simple flavors which need to be carefully dosed within a juice recipe.
Flavor
Flavor concentrates usually come in 10ml or 30ml plastic containers and need to be diluted with base juices in order to create vapable e-liquids. In the case of already mixed flavors like Heisenberg from Vapire Vape or Red Astaire from T-juice one simply needs to dilute 10 – 15% of flavor with 90-85% of base juice (that already has nicotine inside) in order to achieve a very delicious end product.
In the case of single flavor concentrates like Capella (CAP), The Perfumer's Apperntice (TPA/TFA) or Flavor Art (FA) these can make a nice vapable liquid on their own, however they were intended to be mixed with other flavors for more complex e-liquids (this is how most of the e-juices we have on the market today are made). When making such DIY e-liquids it's important to follow the three parts – first mix all the flavors together, then add them to the base juice for steeping (between 3 – 14 days) and finally add the nicotine at the end.
Base
Base juices come in a variety of VG/PG ratios (the higher the VG the thicker the liquid and the higher the PG the stronger the throat hit and flavor) and they can or cannot have nicotine already added to the mixture. I would recommend bases with nicotine for flavor concentrates that are ready to be vaped and for best results bases without nicotine for when creating your own recipes (however this is not a strict rule). 
If you buy your unflavored nicotine base separately it usually comes in 54mg/ml (5.4%) or 72mg/ml (7.2%) but often you can choose between 24mg and 100mg. This needs to be mixed with just the right amount of 0mg base and flavoring for an end result in the concentration of your liking. I usually use Tod Muller's e-juice recipe calculator to know the exact proportions and then with the help of 1ml, 2ml, 5ml and 20ml syringes I measure everything and then mix together in plastic bottles (usually 100ml).
For inspiration about DIY e-liquids there are various websites that offer the exact amount of each flavor (in ml, grams and %) for each user made juice and some of them are really delicious. I would suggest starting with ready to be mixed concentrates (like Hawk Sauce from Mount Baker Vapor) and then gradually making the transition to more complex recipes that require 5-10 single flavors.
