Yep! As previously posted testing a single flavor in water is one way among others. I've heard of others and have my preferred way but whatever works for you is fine.
I use a cheap dripper (
rda) with a Ekowool wick so it's easy to clean and burn the wick to eliminate the previous flavor. Only takes a couple of drops to test each flavor. The final mix is tested the same way. I normally mix at least 2 or 3 small batches of the final mix and work my way
through each batch and take notes. Changing the % of the components in each batch. Sometimes I let them just sit for a few days and return to each batch throughout the day trying to figure out what works best for me. For me, testing each single flavor is only a ballpark guide but should always be done.
Real deal "flavorist" with trained noses and lots of experience use a single drop on the tip of cardboard and wave it in front of their nose. Single flavor and the final mix.
As previously noted, all of these techniques are imperfect but far better than not testing each flavor and thus getting you in the ballpark on a given single flavor. Here is a real world example of how "pairing" can change the final mix.
FA Banana - tested and seems week
FA Pear - tested and kind of subtle but nothing special
Use the above two in a mix and the FA Banana springs to life and becomes much more prominent and the Pear fades to almost nothing. I've also heard of testing a single flavor in cool wip but never tried it. A single drop of a single flavor on the tip of your finger and then a taste. Tried this a few times just for kicks.
Good luck with DIY and have fun!