(Not that it's getting much warmer yet, here, but I'm an optimist. And, the forecast for this week looks good.)
The first cocktail I ever had was a gin and tonic. I was at a catered party with a full bar and didn't know what to order; it's what my friend Steve got me, and it's my drink of choice to this day.
Here's how I make them. In advance, chill the tonic water. Fill a glass with ice cubes. Add 2 oz gin (I like Hendrick's; the smell as much as the cucumber-y, green flavor). Add one quarter to one half a squeezed lime, to taste. Top it off with 6 oz tonic water (I like Fever Tree tonic water - it comes in 6 oz bottles), stir well, and enjoy.