Behold the diminutive yet mighty tippet ring. Depending upon your perspective it might be the greatest thing since sliced bread or may represent the end of civilized fly fishing as we know it. They usually come packaged something like this and can easily go unnoticed in a fly shop among more eye-catching accessories.
Although the handy snap swivel is designed for on-stream use, I've found my tying bench to be a much better spot for attaching a tippet ring to a leader. With pre-packaged leaders, putting the rings on prior to fishing is the way to go.
And whenever you're messing about with leaders, a leader gauge is a wonderful tool to have.
Most pre-packaged leaders come neatly coiled but if you're not careful when uncoiling them bad things can happen. To avoid such catastrophes, insert the fingers of your left hand into the coil like this and then, starting at the loop end, unwind the leader from around the coil. In most cases, this means removing 5 or 6 turns. You should notice if you haven't removed all the turns. While applying outward pressure with your fingers, slowly pull the leader from the coils. Keep doing this until the very end of the tippet and you should wind up with a nice straight leader as opposed to a tangled mess.
To add a tippet ring, go up about 2 feet from the very end of the tippet. On this 9' 5X leader, at this point, the leader gauge indicates 8. This means it's .008 inches or 8/1000th's of an inch in diameter or what we commonly call 3X leader material.
Snip the leader at this point but keep that tippet that you cut off. Get hold of your tippet rings and isolate the ring closest to the snap opening. Make sure you have the closest one. With the ring isolated, insert the small end of the leader, not the tippet, through just the ring and secure it with your favorite knot. Once you have the knot seated carefully, open the snap and take off just that one ring. Then carefully re-close the snap, doing your best not to shoot microscopic tippet rings all over your fly tying bench in the process. After you get the tag end trimmed off, this is what it should look like.
You can then tie on that 2 feet or so of tippet you had cut off of the leader. The whole ring and knot combo is so light that surface tension causes it to float most of the time. A light application of a quality floatant will help to ensure the ring rides high and dry on the water's surface.
I'll usually just coil a freshly ringed leader right back up and return it to the package from which it came so it's easily identifiable, well protected and ready to fish at a moment's notice.
For me, the best part about using tippet rings is they allow leaders to last almost indefinitely while at the same time make it far easier for me to rapidly change tippet material.
As you can imagine, changing tippet is a really good idea after a protracted battle with a large fish while using light tippet, like 5, 6 and especially 7X.
To change tippet, just snip it from the ring right at the knot. Dispose of it properly. Pull 2 or 3 feet of new material from the tippet spool, snip it off and then tie one end back onto the ring. Snip off and properly dispose of the tag end and you're ready to fish.
In addition to tippet rings, micro-swivels like these that test at 45 pounds can also be used. They work great, especially for large streamers that tend to spin. Although even the smallest of swivels dwarf a tippet ring, they're still really tiny and go largely unnoticed even when casting. To me, both are worth a try. If you don't like them, don't use them. But you never know, it might be a match made in heaven.