1. Scout It Out
2. Study, Study, StudyLook for anything that strikes you as different, providing habitat for the rainbow trout. Study everything from endless eddies and side channels of your favorite runs, to the foamy edges of the main currents you rarely consider. Look for rising trout. If there's a hatch coming off, but you don't notice any fish, you might not be looking close enough. In the fall and winter, rises are so lazy they barely make a ring. So sit back, and let your eyes do the fishing. Scan for those telltale boils that will only appear today, and will surely hint to good fishing below when the water levels soar in coming months.
3. Search the ShallowsBe sure to search the shallow stretches for any places a trout is likely to feel safe. Some ideal holding spots include undercut banks, beneath and beside logs and below overhanging brush or tree branches. These are prime holding when rivers swell with snowmelt and leave the water stained and fast-moving, forcing trout to hug the banks in search of protection from the strong currents.
4. Find Feeding ZonesKeep and eye out for all the areas that will provide fish with food. Find pockets (behind boulders or at the bottom of pools) where trout can camp out eat without expending a ton of energy. Trout can start getting sluggish in the offseason and aren't willing to go out of their way for food. Find a concentration of these winter whoppers holding in a food-carrying current and you've probably stumbled across that "secret spot" for the rest of the year.
Deep pools are obvious big-fish magnets, but also see plenty of pressure throughout the year. Look past the bottomless holes and seek out other key strike zones that won't catch your eye later in the year. Note seams where strong currents flow into slower, shallow-water riffles.
5. Watch the SurfaceDon't limit yourself to reading the river below the surface. The surface is probably the most telling aspect of the river. Dancing pyramids (where slow water meets faster water) can hold nice fish even if cover isn't present. Standing waves mean there are big boulders ahead and big fish hiding out beside them. Eddies are easy giveaways for fish.
Don't forget the importance of boulders and other structure that break that surface given they'll be completely submerged once the runoff begins. Large rocks provide pockets downstream and will continue to provide tail-end cavities all year long. The same goes for large logs, or concrete slabs and other man-made structure that ends up in the river.
6. Ready Your GearAnother key during the offseason is to keep your gear in check. If you're in need of a replacement rod, reel or other key fly fishing accessory, the end of the year is always a good time to find bargains on year-end closeouts of the previous year's models.
The offseason is also a good time to repair and clean your gear to make sure it'll hold up for another season.