[axle27]

The way I do it this:

I thread the line throught the fly (or lure).

Make a loop about 1.5" long (approximately) then hold the tag line and main line between my thumb and finger.

Insert the hemo into the the loop and twirl it 5 or 6 times to get the twists.

Grasp the tag line with the hemo's and pull it back through the loop.

At this point, I put down the hemo's and grasp the tag end in my teeth. I pull the main line and the lure directly away from each other while holding onto the tagline. Once the knot is cinched down on the fly (or lure), I test it to see if slips.

If not, I cut the tag and off we go.

It's an excellent way of doing it for flourocarbon as this stuff can be a bear to tie this knot with. Beats the heck out of trying to twirl or twist the lure/fly/swivel in your fingers and run the tag line back through the loop.

[Rip Tide]

As we all know, knots slip when they're not seated correctly
With a clinch knot, the number of turns you make around the standing line determines how well the knot will seat
Heavy mono may take only 3 1/2 or 4 turns, light mono might take 7 or even 8
The only way to tell is if you make the turns by hand
...You will be able feel the resistance and subsequently, you will know when to stop when you've made enough turns

I've given up on the 'improvement' of the clinch knot and follow this simple rule instead.
...works for me...

The same rule applies for any fishing knot where you make turns around the standing line
The uni-, blood knot, non-slip......

[Fly2Fish]

I really like Kai's suggestion (which would work just as well as the tool I now use). Also, Rip Tide is absolutely right when he suggests varying the number of turns depending upon the tippit size.

As to the difficulties some have mentioned about tying the Improved Clinch when using very small flies, it is much easier to tie the regular Clinch knot instead. I have seen research articles concluding that the regular Clinch knot is stronger than the Improved Clinch. In my experience, the regular Clinch knot is much easier to tie than the Improved Clinch - particularly on small flies - and I have never had a fly break off when using the regular Clinch, either from the fish or from a snag.