3 dries I would recommend that I use for lake fishing with success are
1. parachute adams
2. parachute hares ear
3. elkhair caddis
you can do a search and get the pattern receipe off the web for 1,3 but I tie the hares ear a little different,
tail: mixed brown and grizzley fibers
body:a mix of antron and hares ear dubbing
rib: fine gold mylar
wing: white antron post with brown and grizzley hackle wrapped
I like small sizes and rarely go bigger than a 16 and lately (the last couple of years) I've been tying alot of tiny dries which the parachute style works very well for and is fairly visable at a distance plus the fish really seem to go for them.
THIS IS MY STAND BY FOR ANY DRY FLY
GRAY TURKEY FLAT TAIL, GREEN SUPER FINE BODY (VERY THIN), GRAY POLY FOR A POST (YOU CAN USE WHATEVER, BUT I LIKE THE POLY), AND GIRZZ. GRAY HACKLE.
IF THEY WANT SOMTHING A LITTLE BIGGER I SHOW THEM THIS
LONGER SHANK DRY FLY HOOK, TIE IN YOUR FAVORITE HAIR (IE ELK OR DEER, ETC.) HALFWAY DOWN WITH THE TIPS FACING BACK. DUBB UP YOUR FAVORITE COLOR BACK TOWARDS THE EYE OF THE HOOK (I USE KAUFMANS STONE FLY MOST OF THE TIME. BLACK AND GOLD), PULL THE HAIR BACK TOWARDS THE FRONT, TIE IT OFF AND THEN TURN IT AROUND AGAIN SO THE TIPS ARE FACING TO THE BACK AGAIN, DUB A HEAD IF YOU HAVE ROOM, YOU COULD EVEN ADD HACKLE IF YOU WANT, OR JUST TIE IT OFF AND CALL IT GOOD IF YOU ARE CLOSE ENOUGH TO THE END.
I GOT THAT PATTERN OFF A WEBSITE WHEN I FIRST STARTED TO TIE FLIES. I HAD WHAT IT NEEDED AND ONCE I GOT MORE STUFF, I WOULD CHANGE IT HERE OR THERE TO GIVE ME WHAT I NEED. THERE IS A PICTURE OF ONE OF MINE IN THE BLIND MANS SWAP FROM LAST YEAR.
Sean suggested the classic elk hair caddis (EHC), which no one will complain about. But, I've found that I have switched over completely to fishing an X-caddis when fish are feeding on caddis. The X-caddis is easier to tie and more effective because it rides lower in the water and simulates the caddis fly profile better. I still use the EHC occasionally on fast moving high mountain streams where bouyancy is critical and the fish are naive.
The X-caddis differs from the EHC in two minor ways:
1) add a tail of z-lon or antron or other wavy poly fiber. Keep it sparse; 6-8 strands is enough and about half the length of the hook. I like an off-white or dun color, but others can work.
2) Leave off the hackle palmered over the body.
The fly that has been my favorite the past couple of years is the CDC emerger. This is also easy to tie and can represent either an emerging mayfly or caddis.
Tail: z-lon (just like X-caddis)
Body: dubbed slender (olive, tan, or etc.)
wing: clump of CDC fibers tied in with tips back and butts towards the eye. These should be 1/3 way from eye to bend of hook. Jam enough together so that they provide enough floatation; at first I used too few. Also, I used to use various colors of CDC, but have settled on natural for all of them now, HOwever, I use a few wisps of whited dyed CDC on the very top of the wing (the top bits of CDC when you tie them on), which helps make this fly visible. Otherwise this is a very hard fly to see on the water.
Head: a bit more dubbing over the CDC butts.
I often use this as a dropper 18-24" behind either a X-caddis or mayfly pattern like a parachute Adams.