I admit it. I have never mastered the difference between "lie" and "lay". I wish the powers that be would just issue a pronouncement changing those words forever. My usual tactic is to simply write around them, using "set" and "recline" instead. Those words, you can keep straight.

I found a few sources that might help, if you are similarly challenged. English-Zone.com has a handy lay-lie quiz; I scored 70% - not great. Sometimes it helps to see the words used in sentence form. That makes more sense to me than trying to remember what a transitive verb is. Likewise, you might find this long explanation helpful, but it just confused me. Gerald Grow at the Florida A&M has put together some more comprehensive exercises that might help, too.

Now, I need to go set my head on a pillow and recline on the couch after all that.