I found that charting was extremely difficult because I have small children and often at least one of them comes to my room a few nights a week. If you get up in the night or even waking up in the night, it can throw off the whole temperature thing. I found the best way was to use the ovulation predictor kits. My husband and I chose to use the ClearPlan Fertility monitor which was expensive but oh so worth the money. A friend of mine was able to be go to an online auction and buy hers for half the cost and it was still brand new, never been opened, sealed, and still had rebate forms, etc in it (she couldn't use the rebate though, it wasn't purchased through an authorized dealer).
I found that even though I had been charting, my ovulation was off from when I actually thought it was and I was charting EVERYTHING from cervical mucus to body temp, to what I ate, to what happened in the night, etc, etc. But...with the computer monitor....I got pregnant the first try! YEAH!!!!!!