Its not a secret or trick. When you sample flavors of different types (TFA, FA, FW, etc....) you will find juices that taste differently and have different effects!. For an example lets take two of my favorite workhorses.. FW Sweedish Fish and FW Ecto Cooler. Both of these two give a strong inhale flavor and aftertaste. The peel orange flavor lingers on the tongue in the ecto, as does the Sweedish Fish.
Now taking those two facts, I would look for a flavor that has a more of an exhale taste and add them together. (I do find some Mints do this, Koolata does as well). Play around until the effect touches each. Share the juice and your friends think you've made magic!
When you make your first "single" flavor juices keep in mind the overall feel of the juice in your mouth, lungs, and nose as you vape. What do you have that PAPER FOR? Write it down!
KNOW your Juice, Feeeeel The Juice.
Ohh and if we're talking mixing fruits, ever hear of a neat way to make fruits pop?
Add 1 drop of lemon juice per 5mls. Real Lemon Juice.