A or an?
You’re thinking: I learned this in grammar school—a before a consonant and an before a vowel. But it’s actually a bit trickier. Use a before the sound of a consonant and an before the sound of a vowel: a swim meet, a basketball game, a USMS sponsor (the U in USMS sounds like it begins with the letter Y), an open-water event, an award, an NCAA championship (the N in NCAA sounds like it begins with the letter E).
You may not remember from grammar school what a split infinitive is, but you remember you’re not supposed to do it! An infinitive is the form of the verb combined with the preposition “to,” as in “to swim”; the infinitive is split when a modifier is inserted between “to” and the verb: to rapidly swim. Although it’s true you should avoid splitting an infinitive if it sounds awkward, sometimes it sounds more awkward if you don’t split. Which sounds better: "to boldly go where no one has gone before" or "to go boldly where no one has gone before?"
Ending a sentence with a preposition
You were also probably taught not to end a sentence with a preposition. Don’t worry about it. Rewriting a sentence to avoid ending with a preposition usually results in a more awkward-sounding sentence than if you’d just left it alone. Which sounds worse: "Ending a sentence with a preposition is something up with which I will not put" or "Ending a sentence with a preposition is something I won’t put up with."
Make sure a modifying phrase has a subject in the sentence to modify: WRONG: "As a swimmer, water temperature is very important to me." The subject of this sentence is temperature, so as a swimmer can’t logically modify it. RIGHT: "As a swimmer, I am concerned about water temperature."