The clinch knot
The clinch is tied in a single strand rather than a doubled one, and that is exactly why it works where the Palomar does not. The Palomar loop has to pass over the whole lure; the clinch only needs the tag end to go through the eye.
How it is tied
The line goes through the eye, the tag wraps around the standing line — five to seven turns — and the tag then goes into the small loop right at the eye. Wet it and draw it up, holding the turns so that they seat in an even row.
The turns must lie one beside the other and must not cross. A crossing is a break point, and on thin line it decides the outcome.
What «improved» means
The plain clinch stops there, and on slick line it creeps. In the improved version the tag, after the first tuck, also goes into the large loop that has formed along the turns — and it is this second tuck that keeps the knot from shifting.
One extra move, and it holds differently. That is why references almost always mean the improved version even when they simply write «clinch».
Where it beats the Palomar
Wherever the loop will not pass. A large plug, a heavy spoon, a bulky jig head — the clinch does not care what hangs on the end, because only a single strand goes through the eye. The same applies to a very small eye that a doubled line simply will not fit through.
This is precisely the case the card on the Palomar points to.
It is weaker on braid
The clinch holds by the friction of its turns, and braided line is slick — the same number of turns is not enough on it and the knot creeps. There are two ways out: add turns, or tie the clinch in doubled line, which is what the Palomar is from the start.
On monofilament and fluorocarbon the problem does not arise, and there the clinch works as intended.
What else it is tied to
A swivel, a snap, a clip, a lure ring — anything with an eye. On a snap the clinch is more convenient than the Palomar for a simple reason: the snap does not have to be passed through a loop, and that is the slowest part of the Palomar.
Because of this the clinch often stays the «snap knot» even for anglers who tie the hook with a Palomar.
How many turns
The rule is the same as for the other knots: the thinner and slicker the line, the more turns. On thick monofilament extra turns keep the knot from seating; on thin line you add them instead.
What not to do
Do not draw it up dry: friction between the turns heats the nylon. Do not trim the tag flush — under load it pulls back into the knot. And do not «tighten up» a knot that has crept: it is retied from scratch.
A finished clinch sits hard against the eye, the turns lie side by side and the tag points towards the lure. A knot standing a few millimetres off the eye is usually under-tightened: the turns have not seated yet.