Dotting the t’s ...
Grammatical detail. To outsiders it's boring and it can make proofreaders the subject of derision. Punctuation in particular draws a special kind of bewilderment. Not only is it generally misunderstood, it can be utterly ignored and put in the oddest of places. The success of Eats, Shoots and Leaves proves that there are still people who care; if you work with the written word and can't afford errors, you should be one of them. If you're not 100% sure, hire someone.
and crossing the i’s
What's more, punctuation changes over time and there are exceptions to the rules. Plurals (apple's, monkey's) don't have apostrophes. T's and i's do. There's a difference between 1960's and 1960s. Its and it's continue to confound. Semicolons, colons, commas and full stops get used interchangeably. The rules of listing commas and quotation marks depend on which side of the Atlantic the writing is for. I'm beginning to hate proofreaders.