Just a tip for any one that is new and has no idea where to start with a flavor...
I will uncap the bottle and hold it about 12 inches under my nose. Then I judge how it smells. If you can't smell it at all, or it is very faint, move it an inch closer. Keep moving it closer to your nose until you hit that "sweet spot."
If you can put the bottle right up to your nose, and it still smells good and accurate (not like perfume) then it is most likely a flavor that you can go crazy with (20%) and not have any problems.
If it starts to smell weird/inaccurate/perfume at 10 or 12 inches from your nose, it is VERY CONCENTRATED and you should be using it in low percentages (2% or less).
If you find that it doesn't smell much at 12 inches, smells great at 6 inches, then starts to smell weird at less than 6 inches, this is a medium strength flavor and should be used in the 5-10% range.
Please remember, when someone posts a suggested percentages, it is their own opinion. Everyone's nose/pallet is different, and this is a way to find YOUR sweet spot.
I need to trim my nosehair so I can actually smell. It also fucks up my ability to be a dragon when vaping...
That's great info!
I use a different method though because I find my 'bare' snout unreliable and I often have vapor's tongue.
I use the "shot glass method". I take 1oz of luke-warm water (perfect size for mouth), add one drop of flavoring, smell, shoot, swish, spit, inhale, exhale (nose/mouth depending on flavor).
I kind of feel like I'm letting the cat out of the bag here, but I just won the /u/NudeNicotine raffle so I need to re-up some real life karma. It isn't novel though, it's the same/fastest way you learn what the all those spices in your cupboard taste like, their relative potency, and how they play together (some of those require oils though).
You quickly get a feel for the flavor and intensity and can start riffing in your head. All those flavors in the back of the drawer that you haven't gotten around to trying? Yeah, time to taste them, it'll take you but a minute.
A rough guideline would be around 1d = 4% (I'm guesstimating here as I'm not near my kit and never thought to standardize it). If 1 drop is perfect, play in the 3-6 range, If two are needed for the taste you're looking for, maybe 6-9. That scales for back-notes as well. I've found they play pretty damn close to juice regardless of percentage. This is especially helpful for testing wacky mixtures without fucking about with dozens of micro mixes and hours of swapping cotton. Lay the profile down in water first (or vodka for a fun drinking game), then fine tune the right amounts for vaping.
Try it out, mix up a "shot" of your favorite juice, and let me know how it works.
Remember, these truly are water-soluble FOOD flavorants and "bloom" once they mix, which is why water works so well. You can also gauge the PG/VG/Alcohol content of your flavors this way (candy making anyone?). VG will drop like a BB and 'claw' along the bottom, PG will drop similarly but leave a wispy trail, alcohol will hit the surface and go poof, gone.
note: If you are firing through mixes, be aware of their solubility. If you throw a flavorant like pear or any citrus (often containing more alcohol) against something like tea or tobacco (PG/VG), you'll need to use hotter water and/or mix them together with purpose.
caveat: This method is obviously not foolproof, nor can you create the perfect juice through 'swishing'. It is simply an invaluable first step whenever you receive a new flavor and an enormous time-saver when playing with new ideas.
Edit: In hindsight, juice ordered at 0mg may also be easier to clone using this method.