Unless you are collecting seeds and plan to resow the area, never pick all the plants from one plot. You want the source to be productive for years to come. Gather 8 - 10 stems in a bundle. Make sure the flowers are arranged so that they are not clumped unevenly. I will sometimes use these bundles on wreaths or swags just as they are and other times I will take the bundles apart to use the stems separately.
Smaller bundles dry more quickly.
Tie the bundles off with rubber bands, floral wire, string or pipe cleaners. As flowers and plants dry, they will shrink. Rubber bands tend to shrink with the plants but must be cut if you are planning on using the stems separately in designs. In otherwords, if you are going to use your bundles as is, then rubber bands are the best way to go. If you are going to separate the stems after drying, use floral wire, string or pipe cleaners.