Triple Sec is also known as Orange Curacao, it is a cheap low grade, low proof orange liqueur. If it's your B-day, truly a special occasion worthy of a special cocktail, bag the Triple Sec altogether and buy yourself either Grand Marnier or Cointreau and substitute one of those for the Triple Sec (I'd suggest Grand Marnier out of the two). You want the worlds greatest margarita? A margarita that'll blow your doors off? Here's how you do that:
First, and I know it sounds like a pain in the ***, but it's really not, even with a hand-held citrus juicer, YOU NEED TO MAKE YOUR OWN HOMEMADE SOUR MIX. Yes, I know they sell a coupla ready-made margarita mixes in the store, but it's your damn birthday and dammit, you deserve it. And besides, the difference between that crap in the store and this stuff I'm about to tell you how to make, is stark raving freakin' unbelievable. Trust me OK? Here it is:
1 cup lemon and/or lime juice, FRESH SQUEEZED (use both, adds more depth to the final product).
1 cup distilled or spring water, tap if you must.
Half cup cane sugar, more to taste if preferred (using light brown sugar isn't bad either, especially for caribbean based cocktails). Stir until dissolved.
Some egg white (1-2 oz) can be added to this in order give your cocktail a nice frothy head after shaking. It's optional though.
Now you've got your sour mix, the rest is way easy.
In a nice tall 12 - 14 oz glass (assuming you don't have margarita glasses), fill with ice. Add about 1.5 - 2 oz good gold tequila (yes, Cuerva Gold is fine, no need to totally blow the budget). Add 3/4th - 1 oz Grand Marnier. Fill glass with your homemade sour mix. Transfer contents of glass into a cocktail shaker-shake it like the San Francisco earthquate would shake it. Salt the rim of your glass (NOT table salt, either Kosher Salt, or Cuervo sells ready-made margarita salters). Pour contents of shaker back into your glass. Float a little more Grand Marnier on top, Sip. Slurp. Then try to find all your doors that were just blown off.