When you are new to sewing with knit fabric, it might be a hassle to find your preferred way of finishing hems. It also depends of what type of knit fabric you are working with. Learn how to stabilize a knit hem with fusible tape.
Sewing a muslin is a great way to test out the construction and fit of a sewing pattern without the risk of wasting good fabric and a lot of time on a garment you ultimately aren’t pleased with. Learning how to fit a muslin is an invaluable skill if you enjoy garment sewing.