Biggest problem most people have -- How to get a straight edge on your work? Great tutorial that "demystifies double crochet" so you know how to crochet the end of the row, turn, and start the next row. It gives you straight edges this way.
Excellent write-up on how to read crochet patterns. Great tips on things that aren't specifically written into patterns their just inherent. Plus the basics on learning stitches, what to do with asterisks, parenthesis, etc.