Fill your glass with ice.
Place 5 or so mint leaves in your cocktail shaker.
Use your jigger to measure .5 oz of simple syrup and 1.5 oz of lemon juice. Add those both to the mint leaves in your shaker.
Take your muddler and use it to gently smash the mint leaves in with the lemon juice and simple syrup.
Fill your shaker full of ice.
Add 2 oz of Gin by measuring it with your jigger. Add the gin into your shaker.
Put the top on your shaker and then shake well. This usually takes about 15 - 20 seconds.
Trade the shaker top for the Hawthorne strainer. Pour your drink from the shaker into your glass.
Grab a few additional mint leaves and add them to the top of the glass.