If maintaining a beautiful garden is about creating a series of beautiful pictures, then the most important part of the act of creation is editing.  To put it in a less artistic way--cleaning up is one of the best things you can do for your garden.  For example, my blackberries have finished bearing fruit for the year.  For the health of the blackberry patch and the beauty of the area around it, I need to cut back the spent canes.  The daylilies have mostly come and gone.  I generally let the foliage ripen a bit, then cut it back so that the asters and other late summer and early fall flowers can shine.

Of course there are a few exceptions to this rule.  Once blooming roses often form lovely hips, and should be left alone.  Some clematis sport interesting seed heads that deserve a moment (or two) in the sun.  On the whole, though, it's a good idea to carry a pair of clippers with you on your daily trips around the yard.  That makes it easy to clip spent stalks, leaves or branches.