This post is about the beginner recognizing the pretty obvious progression of a pattern of tying, but also, a strong reminder that these basic patterns would and do take an enormous amount of freshwater fish. We often hasten our tying experience toward more complicated patterns (hence they must be more worthy) and leave behind simple patterns, that are fish magnets. The above pattern is representative of such a pattern. It could be tied from a size 2 to a size 18 and take countless fish. Body and hackle colors could be mixed and matched. You will note that there is no tail. The Woolly Worm is often seen with a red tail of red hackle fibers/barbs or a tuft of red synthetic yarn. The red tail is traditional, but a more subtle color could be used.
The below pattern is a thicker view of a Woolly Worm with the tail.

You notice the fly is thicker with the chenille body and the prominent red tag tail of yarn. The tail is theorized to be an attractor. The body of this Woolly Worm is similar to that seen in recent years for the fly shop Woolly Bugger…

The late Ed Story of Missouri, tied the Crackleback pattern, akin to a miniature Woolly Worm, which he fished top to bottom and touted as his primary fly via his Feather Craft enterprise.

I hope you can see the simplistic beauty of this basic tying premise and not hasten away from it. Large and small, top to bottom, the basic bones of these patterns must not disappear from your fly box. A basic technique in all of them is palmering the hackle, usually rear to front. The hackle is tied in by the tip and wound forward, incrementally spaced out, over the abdomen/thorax area and tied off at the head. How you tie the hackle onto the shank determines whether the hackles angle forward or as most often backwards. Above in the Crackleback, the feather was tied in with the underside of the hackle facing forward; this caused the hackle barbs to angle forward. Usually the feather is tied in with the top or shiny side of the hackle facing forward; causing the hackle barbs to angle backwards. All of these patterns will be affected by the degree of stiffness in the hackle used.