Oh god, DON'T cut your limes too early.
And know the difference between a regular lime and a key lime. You might get a bit of a shocker if you get a twist made with a key lime or a key lime martini done up with regular persian limes, whew! I never, ever keep them in the fridge, though. And in a pinch, there is one brand of key lime juice you can get away with... I'll find it at the store and pass it along if anyone is planning key lime pie martinis (which are fabulous, by the way, but cream-based).
Another mistake, though not listed, is keeping your other citrus juices too long. OJ, pineapple juice (especially in cans) and grapefruit juice age and become more bitter. If you can't do fresh, think about freezing them into ice cube trays and defrosting at room temp.
If your herbs are aging too fast (like your mint for the mojitos) consider freezing them in water and defrosting as needed.
Oh, and don't sub Splenda for sugar. Especially not on the rim of a glass.
