Put the sugar in a cocktail glass and shake over several dashes of bitters. Add a splash of water. Stir to dissolve sugar. Add ice. Pour in whiskey. ( If you like, top off with a splash or two of club soda.) Garnish with a twist of lemon peel.
My father used Bourbon and never watered Bourbon. (Water rusts Bourbon, he said.) He used 2-Cents Plain. It was impossible to find for a few decades; now it's around again. Maybe it's a geographic thing. Personally, I like Rye and Schweppes in the summer. I would consider the lemon twist just a garnish unless it's rubbed 'round the rim. The maraschino cherry is tasty... reminiscent of a whiskey sour.
Used different ingredients.
Muddle a slice of orange!, you can put the sugar cube in at the same time you are muddling. Put this mixture in glass, add rocks, whisky, bitters and a maraschino cherry.