I took the Humanities CLEP almost 2 years ago. I'm copy/pasting the thread where I discussed it. It was reasonably easy for me but I had substantial exposure to arts & music due to dear mom (thanks!) but I had to brush up a lot on literature.
I used www.degreeforum.net to study for this test. They have a monthly service where you get access to flashcards for the various tests. You also get access to their member only forum which has a lot of great tips on what to study for the tests. It is like 20bucks or something for a month. I used just that degreeforum site and cramed for like 6-7 hours and passed the sociology CLEP.
A thing to remember about CLEP tests is that they are pass/fail. Don't spend a ton of time aiming to get an A on the test. Just strive to get the pass and move on.
I hear the best clep for humanities is Analyzing and Interpreting Literature. Some people studied for only one day, some people didn't study at all. Its mainly reading comprehension and some terms like anomotopea and then I think some Shakespeare and other poet questions. Type a&i lit or "analyzing and interpreting lit in the search box to read other peoples experiences. Its 6 credits! An easy 6 I hear! I forgot the recommended books but I know rea clep books are good and whichever book I looked into that was recommended had good reviews. Sg101 also has a free flashcard download for a&i lit and other clep exams.
For sociology, Ive heard people cram in only 6 hours of study and pass. I plan on buying the REA sociology book. Heard great things.