In a cocktail shaker, add the strawberries and agave syrup, and start muddling them. Add the basil leaves and continue muddling until they release their juices.
1 cup sliced fresh strawberries, ¼ cup agave syrup, 6 fresh basil leaves
Add the tequila and lime juice and shake to combine.
½ cup tequila, ¼ cup fresh lime juice
Rub a lime wedge around the glasses and dip them in salt.
Lime wedge and sea salt
Fill the glasses with ice, pour the margarita into the glasses, and garnish with strawberries and basil leaves.
Ice, Strawberry slices, Basil leaves
Video
Notes
It's really important to use fresh basil.
Use fresh strawberries if possible, but you can use frozen strawberries in a pinch.
Use fresh over bottled lime juice, although both will work.
Use blanco or silver tequila for the best flavor. Reposado will also work, but it may lend a darker color.
Use agave or honey for the best taste, although simple syrup will also work.
Feel free to make a salted or sugared rim.
Shaking the cocktail is key. It aerates and mixes the ingredients much better than stirring.
Use large ice cubes to prevent the margarita from getting watered down too quickly.
If using a jigger, be aware of the measurements. The larger size is one jigger or 1½ ounces. The smaller cup is normally one-half jigger, or ¾ ounces.