There are plenty of free instructional videos on youtube.com. You can also purchase inexpensive instructional DVDs by professional hair stylist to improve your technique. Just remember to take it slow and practice by taking little length off at a time.
A favorite hair cut is blunt. You don’t have to take off much length. And it can help fine hair look thicker because each strand is the same length.
For blunt hair:
Start with either dry or wet hair. For curly hair, it is best straighten first. Brush or comb the hair to remove all tangles. Make sure hair is as straight as possible and your hair is parted naturally. Starting at the back of the head, section a small part to serve as a guide. Cut a quarter of an inch of hair. Make sure to not pull on the hair. Let it fall naturally. The shears should be held horizontal and cut straight across. Shears should be sharp and made for cutting hair only.
*The above instructions are general instructions. They do not serve to replace a professional.
Photo credit: Stuart Miles | Freedigitalphotos.net