http://www.bonappetit.com/test-kitchen/how-to/article/how-to-dry-herbs 
oregano and mint all maintain most of their original aroma and fragrance once dried, making them ideal candidates for this project.(Credit: Matt Duckor)
Few things love warm rainstorms and abundant sunshine more than the herbs of summer–and if your window box looks anything like mine, things are getting pretty out of hand. Sure, we love using fresh leaves in salads, to make pesto, or for those salsa verdes, but there is an easier (i.e., lazier) way to reap the benefits of all that shrubbery: clip them and leave them out on your counter to dry. Within 48 hours, you should have dried herbs, ready for storage and for helping you through the winter.
HOW TO DRY FRESH HERBS
Pick the leaves from the stems and lay them on a piece of parchment. Leave them in a draft-free area, like on your kitchen counter. Once completely dried (this should take about 2 days), store them in glass jars or containers. You can store each herb separately or mix them, depending on your preference. The combo of oregano and marjoram is a natural for all things Italian (your Sunday gravy will thank you) and oregano and mint make for a lovely Greek-inspired rub for roast chicken or leg of lamb. Before using, crush the leaves slightly to release their essential oils. Shelf life for most dried herbs is about 6 months. The test? If the aroma is gone, it’s time to let them go.