I'd always been intrigued with making a giant granny square afghan so I started following a pattern that I found in a book I recently got from the library. After crocheting for a while I noticed that something was going terribly wrong. It wasn't laying flat at all and I knew that it was only going to get worse. I found a leftover granny square from an afghan my mom had made and noticed that it only had 3 double crochets in each grouping - not 4 like the pattern I was following called for.
So I ripped it all out and started over again and as you can see it worked out much better. Most of the time you can follow a pattern and it will turn out just fine but don't hesitate to make adjustments as neccessary.