Lay vs Laid vs Lie

Recently, I began editing Prince Charming, Book 2 in my Honey Creek Royalty series. One word, or words, plagued me throughout my journey.

Lay, laid or lie.

Even now, after I've done some research, I'm still confused.

Here are the definitions of each word:
laid: past tense of lay, verb (per a google search)
lay: to beat or put down with force; to put of set down (online Webster dictionary)
lie: to be or stay at rest in a horizontal position (online Webster dictionary)

Clear as mud, right?

I did a little more research and found this great website called Grammar Girl. (The site looks like it's sponsored by MacMillan) Here, she included a chart that breaks down the present and past tense of this word and recommends printing it out and taping it to your forehead (not really, but I might as well).

I'm sure I'll still get caught up with these words when writing. After all, my characters need to lie down eventually! But to keep me on track and hopefully ease my editors pain, I'll use this new resource. This particular article is a little dated but the English language hasn't gone through any sort of major changes. Or none that I'm aware of.

Good luck on your writing and if you have a word that stumps you time and time again, share it and we can all learn from our mistakes.

Thanks!