Let’s talk for a bit about keeping your desired flavor where you want it
For those times that you want a dominant taste to rule the drink, you’ll find that 2 parts of the dominant ingredient modified with 1 part of its opposite brings balance to the flavor but allows the dominant to remain in the foreground.
For example: sweet to sour, sweet to bitter, bitter to salty, acidic to sweet, etc.
When I want pure balance, a 1 to 1 ratio is called for although there are some flavors that are so intense that you can balance their opposite with a much smaller amount.
For example a berry liqueur is very sweet but you can balance it with the sour flavor of tequila in small quantities. Equal parts of these two will often lower the sweeter flavor so much that you can no longer fully appreciate the flavor of the berries.
This is not to say you can only mix opposites. Similar flavors are balanced the same way. The ratio in this case is used to maintain flavor ascendancy, or intensity rather than basic taste. For example if you find yourself combining two sweet ingredients, you may want to combine a slightly less sweet ingredient to keep the sweetness from becoming cloying.
Neutral ingredients, which do not directly counteract your dominant one, can add volume and additional flavoring while leaving the dominant flavor intact. Neutral ingredients are great for lowering alcohol proof or just adding other touches of flavor to make the drink more interesting.
I consider a neutral ingredient to be anything that either imparts no additional flavor such as soda water or something that possesses its own flavor but does not radically change the existing flavors.
Almost anything that is not the exact same taste or opposite taste as your dominant ingredient could be used for this. Lightly flavored items like lemon-lime soda fall into this category. This liquid has a flavor but it is normally light enough to be hidden under the dominant ingredients.

So try experimenting. Take a flavor you like, start adding either its opposite or a complimentary flavor. Slowly add more of the second flavor and keep tasting. When does the dominant flavor cease to be dominant? At which point does it flip to the other flavor? The only way to learn these flavor transitions is to experiment. Keep mixing and changing portions until you instinctively know when things will flip.

BTW, don’t forget to cleanse the palate between sips otherwise you will still have the prior version dominating your taste buds. Take sips of water, swish it around until you no longer taste the prior mixture. Only THEN should you try the next variant.

Until next time, may all your drinks be tasty. Cheers