Try using fresh strawberries, or raspberries and raspberry vodka.
In a highball glass, drop the limes, then mint, and add the sugar.
Muddle together, but don't break down the mint too much, otherwise, You'll be sipping mint bits.
If you don't have muddler, you can use a wooden spoon, or the bottom of an ice cream scoop handle.
You want to basically crush the juice out of the limes, while using the sugar to grind against the limes and mint to release their oils and flavours.
You're not trying to dissolve the sugar here.
Next pour in the alcohol.
Stir with a bartender's swizzle stick, or whatever you have on hand, don't shake though, cause it'll damage the mint, breaking it apart.
Once the sugar is dissolved (you can usually tell after about 20 vigorous stirs, or when you look at the bottom of the glass and see no sediment), and lots of ice, and top off with soda water, about 3 measure or just to the top.
Stir to mix in the soda water, and drop in a straw and enjoy!