Check out this progression from sketch to each stage of tattooing...
Many nice tattoo pieces require several sittings to finish properly. This raven is still not quite done yet. Stay tuned for pictures of the finished piece. :)
It is also important to have good drawing skills in order to create a nice looking tattoo. There are many books on drawing to help improve your skills. One that we have here in the studio is "How to Draw Comics The Marvel Way" by Stan Lee and John Buscema.
This book is a good starting point for drawing human forms and perspective. Plus, it is interesting and comical (pun intended!). As Stan says in the Preface: "The pages that follow were created to give you an informed insight into the way the most popular comicbook superhero strips are designed and illustrated. They'll bring you as many artistic tips, tricks, secrets, and suggestions as possible. They'll show you what we strive for in doing our drawings, and how we go about achieving our unique objectives in art and design. We've tried to condense our own long years of training, toil, and experience into this one valiant little volume."
If you want to produce nice tattoos, you should make sure you have good drawing skills. Check out this book or the many others that are out there and get drawing! Practice makes perfect, after all! :)