1. Sleep in. During winter there is no reason for hitting your favorite stream at the crack of dawn; unless a cold front is moving in. Typically the warmest part of the day is mid-day to early afternoon.
2. Say no to cotton. Outdoorsy types have a little saying “Cotton Kills”. This is due to it’s poor insulating properties. Contrastingly, wool maintains over ninety percent of its (your) heat when wet. I love the stuff and nothing trumps wool but it is heavy. Try synthetics such as fleece, polypropylene, or some other high-tech lightweight insulating material. Feathers are lightweight but keep in mind that feather down jackets are great for warmth but not very good when wet so leave them home unless there are no chances of getting wet (Hypothermia). Look for great deals at Patagonia, Campsaver, and REI.
3. Fish one handed. Try to fish without too much line handling because it causes ice build-up on your guides and freezes your hands. This is fairly easy if you are nymph fishing. Do this by fishing with a manageable length of line and leader; very much like Tenkara fishing. You’re still going to need gloves. I go fingerless when I can but for brutal days I love my Simms ProDry gloves.
4. Grease your guides. No I don’t mean tipping your guide because that should be automatic. I’m talking about using fly floatant or even better Stanley’s Ice Off Paste and coat your guides to lessen ice buildup.
5. Get your clown shoes on. If you can afford a second pair of boots, get a pair one size larger than your regular boot size. By increasing the size you increase the air and lessen constriction. Also this means you can use a thicker sock without too much constriction. This is one of the reasons boot foot waders work so well in the winter. Boot foots are naturally larger relative to a stocking foot/boot combination. You may also be able to sneak a hot pack in there as well. Try them on before purchasing just in case they are too loose.
6. Fish the bellies. Winter fish hold in many places on a stream but typically they like slow moving water. The belly of a big pool is perfect and it also is more consistent in temperature.
7. Slow it down there gun smoke. No reason to be in a hurry because the fish aren’t. Again I always preface with the are many exceptions when fishing for trout but generally speaking you gotta bounce if off their heads in the winter. That means repeated drifts over the same hold until you arms falls off.
8. Living large. A larger meal helps. I’m not talking nine inch articulated streamers but a hook size or two up from your usual fly size can help.
Bonus. Freezing is fine and dandy. If there is snow on the ground, your chances are better if it’s too cold for the snow to melt. As the sun melts the snow, a super shot of cold water is melted into the stream and often put trout to sleep. The tail of a pool on a sunny thirty degree day is nice.