Tory Burch has helped make the tunic popular, prompting other designers to follow suite. You now have many choices in color, design and fabric. I am including a link to an article my daughter sent from Nashville. I would only add a few comments to these excellent examples and commentary.
Print: Choosing a print that works for you takes some skill. It should complement your personal style. You want to be the focus, not what you are wearing so make sure that you are seen first and then what you are wearing.
Shape: If you have curvy figure with a defined waist, choose a soft fabric or light-weight fabric cut on the bias. You want the tunic to slightly mold around your curves keeping your look feminine.
Details: If your style is feminine, avoid the plain, crisp look of a traditional tunic. Beading or details at the neck will be more feminine as will softer fabrics.