Take time to watch what is happening on a stream before charging in. Look for rises, hatches and sips. Check the underside of rocks and logs to best match what the fish are eating.
An extra rod and reel/spare spools (with different lines on them) are a good idea. You never know when you might accidentally break a rod and need a backup. The spare spool/lines will let you quickly adapt to a wider variety of fishing conditions.
Know your knots inside and out. You'll be able to change flies, leaders and tippets more quickly, and you'll catch more fish.
Pinch the barbs on your hooks. A barbless hook makes hooking fish easier, causes less stress if you're planning on releasing them and is much easier to remove if you catch yourself.
If you're fishing in saltwater, make sure to rinse everything with fresh water afterwards – and wipe your rods and reels dry.
* From the L.L.Bean® Fly-Fishing Handbook, written and illustrated by Dave Whitlock.
When to fish - How Barometric Pressure and Weather effect fish.
