Dan while there are a few of us who can cast the whole line, if you're really already casting 20 yards, you've got more innate talent than most of us. 20 yards is 60 feet, and that is 2/3 of the whole line. Any cast of more than 60 feet generally means that the caster oficially knows what they are doing.
On the special techniques for casting longer, the one closest to a magic trick is the ability to shoot line. "Shooting line" means letting the weight of the cast part of the line pull line out line that is laying nest to you and off the reel. Generally when somebody is making a cast over 80 feet, they will only be carrying 50-70 feet of line in the air and then shoot line for the rest of the distance. "Hauling" is also very helpful in achieving great distance, but that's a much more complicated explanation.
"Pan Fish" is kind of a general term used to describe Sunfish (Bluegill and their cousins), Crappie, and whatever other fish that don't usually grow bigger than a frying pan, hence the PAN fish title. Those size 12 flies are about perfect for sunfish and such, but will also work to catch bass, though not ideal. A fly around size 6 would be more typical for bass.