Make sure your grill is hot, but the coals are lightly layered and not flaming, so ingredients don't become too charred. If using a gas grill, turn the burners down to low. Check ingredients every 30 seconds or so, until they have distinct grill marks but are not ashy.
Use long tongs and a heavy-duty grill glove to pick up and take off ingredients, which are smaller and trickier to handle than meat or fish.
Instead of muddling fruit directly into a drink, you can use it to infuse simple syrups for a more subtle flavor.
Using a mini-smoke box like this one from Weber, you can smoke herbs, berries, and even a cocktail glass by setting the woodchip-filled box atop your grill and letting your ingredients hang out while you flip burgers.