Also, write everything down!!! You may think you'll remember what you used or how much of what you used... but you'd be surprised how quickly you'll forget... Then you make a masterpiece and cannot reproduce it. Also, label your bottles right after you make them for the same reason. I've thought I'd be able to tell which is which by the smell... but again.. you'd be surprised how untrue this is.
Syringes are better measurement devices over drops IMO and most people's... Meaning, calculating recipes by drops is typically unstable/inconsistent. The 1 ML syringes are great for flavorings. 10ML syringes are great for VG/PG. 20 or 22 guage needle is good for the flavorings. The 16 guage is good for the thicker fluids.
I also (personally) use a hot bath for my juices after I first complete them. I use 50/50 vg/pg so my juices are somewhat thick and the hot water makes the VG more fluid, and mix better with the other ingredients. After the mixture is warm, I shake it and let it sit. (steep)
If you create a
juice that is too perfumey, aerating can be helpful... which is taking the top of the juice and letting it air. I wouldn't recommend doing this any longer than overnight (8 hours). It evaporates the alcohol or whatever is making the juice perfumey. Aerating and steeping are different... Some people thinking steeping is when the top is off... and it's not.