I recently took a course to learn how to sew with stretch knit fabrics. I also bought a serger (Babylock Image Wave). It's fun and easy to use.
Here's the top that I made with a nice stretch knit jersey fabric:
The collar was tricky:
Fiona helped me today as I took these photos! She's my Scottie-Poo.
This is a picture of a Babylock Imagine Wave serger. You need 4 spools of thread, it trims and binds the edge of the fabric as you sew.
And here are the side seam stitches on the inside of my new top: