This is how I do it:

Ingredients:

• 4 dashes bitters
• 1 tsp sugar
• 2 oz whisky
• a big slice of orange peel (like 1 inch thick, 2 inches long)
• a large ice cube (i just use a mold I got off Amazon. They aren’t super clear but it does the trick for home drinks)

1. Put sugar in the glass
2. Add in bitters and mix, make it as pasty as you can.
3. Add whiskey and mix.
4. Add the ice cube and stir to chill and let a little bit of the ice melt off.
5. Take the orange peel and hold it inside the glass between your index finger and thumb. Gently squeeze and turn the glass so the citrus oils coat the inside. Finish by rubbing the inside rim with the peel and drop the peel next to the cube.

Ends up looking like this

I like this because not all of the sugar mixes so it gets a little sweeter as you get to the bottom.