Kids love to dress up and pretend play. Your child can wear it to a party or just to dress up around the home. This website offers a superb tutorial on how to make a mermaid tail costume. I would say that you would probably need some sewing experience for this project. The reason being, you would need to make and assemble the pattern and if your not used to this, it could be a bit tricky. However, the sewing itself looks pretty straightforward. Follow the link for the full tutorial; http://www.sparklyarthur.co.uk/blog
If you would like to learn or brush up on other basic sewing skills and techniques before you start this project go here; Sewing Techniques & Stitches to find the skill you would like to work on.
If you would like to see easy/ beginner sewing projects go here; Easy/Beginner Projects
If you would like to see more challenging/Experienced projects sewing go here; Challenging/Experienced Projects