If you want a traditional look for your curtains, pinch pleats, also known as French pleats, are a great option. They may look intimidating, but using pleater tape and hooks makes this project simple for sewers of any level.
You can also easily add a drapery lining to these curtains. Cut the lining the same size as the finished curtain and tuck it under the hems and sides before sewing. For more information on drapery lining, see How to Pick Drapery Lining.