There are two basic methods to dry flowers: air-drying and pressing. One technique might be better than the other, depending on how the dry flowers are going to be used: many crafters, for example, like to use pressed flowers in paper and card making. Dried flowers for decorative use around the home are often air dried so that they retain their three dimensional shape. Consider the needs of the project when deciding which flower drying method to use, as well as your available workspace and the season. Flowers do not air dry well in humid weather, although they can be press-dried year round.
Air-drying flowers is relatively easy to do, although some flowers take better to this technique than others. If you plan to dry flowers by air-drying them, look for flowers without a lot of moisture that have firm, distinctive shapes, bright colors, and rich scents. If you are not sure whether or not a flower will dry well, look for examples of it in a dried form. Seed heads, yarrow, amaranth, strawflowers, cornflowers, and lavender all air dry well. Tie a bunch of flowers loosely together, trim the bottoms of the stems, and hang them, upside down, in a cool dry place. Keep the flowers out of the sun, and make sure to turn the bunch occasionally to make sure that the flowers are drying evenly. When the dry flowers are crinkly to the touch, they are dry and ready for use.
A relation of air-drying is desiccant drying, a useful technique for flowers that do not air-dry well. The most common desiccant is sand, although other commercial products are sold specifically to dry flowers with. To dry flowers using the desiccant technique, lay down a layer of the desiccant in a box, place the flowers onto it, and gently sift the desiccant over the flowers until they are covered. Keep the box in a warm, dry place for two weeks before gently pulling the dried flowers out.
To dry flowers by pressing them, you can either use a heavy book or a flower press. A heavy book such as a dictionary is an excellent choice, as long as you interleave it with protective paper to prevent the book from being stained. Commercial flower presses are also available and relatively cheap. To press flowers, place them carefully inside your press of choice and close it, returning in approximately a week to remove the dried, pressed flowers, which will be flat and papery to the touch.