Knots
If you start the day with the usual 9' or 12' leader, by midday, having changed or lost flies, the length has been greatly reduced and is sometimes back towards the taper. If you do not want to replace the whole leader, you should tie on another length of tippet using a Half Blood Knot, or the more reliable non-slipmono knot. It is also worth trying a small Perfection Loop: a loop is tied on the end of each section of the leader and the two are joined together by the loop-to-loop method. This saves constantly cutting back into the taper of the leader when renewing the tippet length. Any knot is going to be a weak link, but you will find that this method is as strong as any other.
HALF BLOOD KNOT
Also known as the Tucked Half Blood Knot, this old, tried and tested knot is a firm favourite with monofilament, but when heavier monofilament is used it can prove difficult to draw the knot up tightly.

NON-SLIP MONO KNOT
A fly or artificial lure attached with a loop and knotted with this Nonslip Knotwill move around more in the water, creating a better action - whereas a tightly sealed knot will restrict the lures movement. This knot has proved successful with both light and heavy tackle.

THE PERFECTION LOOP

It may seem obvious in joining two loops together but there is a right way and a wrong way of doing this.

Place loop A through loop B, put the free end of B through loop A. (ABBA)

The wrong one will cut through if stressed.
SINGLE UNIVERSAL KNOT
When using the Tucked Half Blood knot you occasionally experience failure, especially with some of the new pre-stretched monofilament material in 6X and below. If this happens, then switch to the Single uni. knot, which is just as simple to tie. For dry flies, pull the knot up tight to the eye, but when attaching a nymph, leave a small loop in front of the eye (sometimes known as the Duncan Loop). This allows the nymph to swing in a more enticing way. The knot will pull up tight when a fish is hooked and can usually be opened up to continue fishing.

A variation of this knot can be used for joining two lengths of tippet material and when tied in this fashion is known as a double uni.