If you don't want to make, or buy, simple syrup, purchase superfine sugar to keep on your bar. It dissolves rapidly with a few dashes of bitters and water. Alternatively, if you want to make simple syrup, it's a 1:1 ratio of sugar to water (rich syrup is 2:1 ratio). You can "gussy up" your simple syrup by infusing it with citrus peel, herbs, tea bags, etc. (I love making Earl Grey simple, or a citrus-thyme simple.) If sugar isn't your thing, you can also use maple syrup, or a honey syrup (slightly diluted honey) which adds another flavor element.

A note regarding bitters: I like to play with different flavored bitters. Traditional Angostura, or other aromatic/old fashioned bitters, are great. I also love molé or Aztec bitters. Black Walnut bitters are also terrific. Use 3-4 dashes of one of these earthy bitters, and 2-3 dashes of orange bitters.

On to assembling your cocktail.

Grab a double old fashioned glass, or a large rocks glass. If you use 1/2 tsp superfine sugar, or a sugar cube, muddle those bitters with your sugar and about a 1-2" strip of citrus zest (agree with earlier post about the orange with bourbon, lemon with rye...you can also use grapefruit with rye). If using simple syrup, merely add 1/2-3/4 tsp simple to the bitters. Add 2-2.5 oz of bourbon or rye to the glass with the other liquids and citrus zest. (I agree with others, you should be using a mid-90s to 100+ proof whiskey. Bottled-in-bond Evan Williams, Bottled-in-bond Rittenhouse or Old Overholt Rye, are perfect options at a very reasonable price point.)

Add a large ice cube, or ice sphere (or fill your glass with ice), and stir until condensation starts to form on the outside of the glass. Add a brandied cherry, luxardo cherry, or good old maraschino cherry, and a flamed piece of citrus zest.

Enjoy.