There are a lot of ways to change the appearance or you lures.  Most of us don’t think about changing our spinnerbait, jig, & crankbait colors without changing lures.  Some days the change needed to make a fish bite can be as subtile as a black line on a crankbait or a red stripe in a spinnerbait skirt.  All you need to make these subtile changes is take a permanent marker with you and add the modification as you need it.  Remember that less can be more and not to over do it.  There are a few companies such as Spike-It, www.ispikeit.com, that make a variety of lure dye and paints which can make the job of modifing your lures something that can be easily done on the fly.