#1 recommendation:
Keep a copy of The Gregg Reference Manual at your desk for memos and general writing.

#2 recommendation:
Keep a copy of the MLA Handbook for Writers of Research Papers at your desk for more technical compositions.

#3 recommendation:
Keep a copy of the Food Lover's Companion at your desk for menu and recipe development.

Compliment or complement?
TIP: If you can say, "I gave someone a compliment", then the word should have an "i" in it.

That or which?
TIP #1: A phrase begins with "that" if it is necessary to the sentence's idea; whereas "which" is not critical to its meaning.
TIP #2: A comma is placed before and after any phrase that begins with "which" (but never with "that"). 

It's or its?
TIP: Because we were taught that an apostrophe shows a possessive, this can be tricky.  Here, the apostrophe indicates the contraction of "it is".

"you and I" or "you and me"?
TIP: Drop "you" from the sentence and repeat it; for example, you'd never say - "She handed the gifts to I." - would you?