This is my favorite dry fly for blugill. It is simple in looks, materials and tying skill.
You will need:
Hook: size 10-12
Thread: black 6/0
Body: size 10 spider foam bug bodies
Legs: medium rubber legs

Step 1: Start Your Thread

Start your thread near the eye of the hook.

Step 2: Attatch Body

Attatch body upside down and so the back is hanging over the eye. Use as little foam as possible (see picture). Then fold the foam down to look normal and put a wrap around it to form the head.

Step 3: Form Middle Section

Make some wraps down the hook shank under the foam, then make a wrap around the foam to make the middle section.

Step 4: Add Legs

Cut four strands of rubber leg material the same length. Make them just a little longer than the body. Pinch two strands of legs near the body on each side and make some tight wraps to hold them in place.

Step 5: Finishing

Work your thread up near the eyelet wher you started. Now just whip finish and apply cement.

For best results in fishing with your spider, twitch it every couple of seconds. I have also heard of people that dont fly fish use these by adding a bobber for weight, and people use these spiders for ice fishing.