I flyfish and I will tell you up front, the most important thing to learn is what fly to tie on. It took me a few years, but I now have a hatch chart for the Whites, giving me an overlapping assortment of prevelant fly's for any given time of the year. Talk to the guy's at the shops, north country angler is a great shop and will help you pick out the possible flys for any given place and time. When your out fishing before you cast a fly look around. I sit and watch for fly's that are out, look for rises in the water and try to determine what they are, turn over rocks at waters edge and if a fly flies by CATCH IT!! and match it to what you have in your kit.
The second thing that is crucial is presentation, you must learn to cast such that your leader gracefully sets the fly down to mimic a real fly, if your fly hits the water at warp speed, the trout will laugh. Remember trout are smart, sneak to the waters edge, dont just run up to the water and charge in, they can see you and will scatter.
One trick that works alot is insects, but some ants,beatles, grasshoppers and walk the shore looking for overhanging trees and bushes, trout wait under them for a clumsy bug. In the morning the grasses that border alot of the Saco are wet, as they dry, the grasshoppers that are wet begin to spring off the grass, many landing in the river BANG, brown trout love grasshoppers.
Practice casting in your yard, watch your line as in rolls out behind you, only when your line is taught should you begin your foward cast, casting back and forth to fast will result in a sloppy release and presentation ( you will find small knots in your line to indicate this is happening (wind knots))
10 and 2, foward cast at 10 back cast at 2. start with 10 ft and add 5 ft at a time and watch your line behind you until you can mentally time it without looking.
Fish eat bugs the magority of the time, if you can get the hang of it you will catch fish. watch them trees as well, youll know what I mean later.
P.S. Ill start you off right, go to any good shop and buy 6 "Henryville Specials" that is the best fly for the Whites period. Ive stood next to the rich dudes in Profile lake more then once and smoked them all with that baby.