OP, don't lose heart. I'm a gourmet cook and I mix the meanest cocktails in town, but DIY'ing e-juice is HARD!
Listen to the advice of those who came before, and never give up. I'm a month in, and to date, I've only ever produced one juice that was any good.
Here is an example of the kind of notes I take... not sure if it will help but maybe worth a shot:
Here are some notes I've compiled that you may find useful:
eJuice Recipe Calculator
ejuice calculator
CAPS = Capella
COV = Clouds of Vapor
FA = Flavour Art
FW = Flavor West
Lorann's
MBV = Mount Baker Vapors
MVS = My Vapor Store
NF = Nature's Flavors
TFA = The Flavor Apprentice
TPA = The Perfume Apprentice
VZ = Vaping Zone
TFA = The Flavor Apprentice - Wizard Labs carries TFA flavorings and they are cheaper to order from Wizard until you get to the 1 oz size bottles, then TFA has a better price. BUT...wizard is out of stock on various flavors a lot.
Check ingredients! Acetoin, diacetyl and acetyl propionyl should not be vaped. Flavour Art's Butterscotch is diacetyl free. On their website they clearly state which flavors do and which do not contain diacetyl.
Coffee Espresso by FlavourArt
This flavor is strong, very strong. Don't be fooled by the flavor before you mix it. The concentrate smells skunky, but once mixed.....perfect. here is the recipe I made .5% (YES POINT 5 percent concentrate), 3% Bavarian cream, and .5% Ethyl Maltol.
Ethyl Maltol
A crystal powder which has the taste of sugar/caramel/cotton candy. Ethyl Maltol is a very pleasant smelling chemical that is used as a flavorant for the food, beverage, tobacco, and fragrance industry. Suggested use: Dissolve 1 gram ethyl maltol in 9ml of propylene glycol. TIP: Warm the propylene glycol in the microwave, then add ethyl maltol powder to the warm propylene glycol. Diluted mixture can then be added to your liquid. Start with one or two drops per 6ml of liquid. Add more or less to suit your taste.
Depending on the concentration of the flavor (normal, super, ultra) you may need to start at a lower concentration. When working with a new flavor I start at 5% unless the manufacturer specifically calls for a lower amount.
Remember no more than 10-15 seconds in the microwave!