If you're going to de-barb your flies (and you really should) do it before the hook goes in the vise; few things more frustrating than trying to flatten the barb on a #20 with wet, cold hands and a pair of hemostats unless it's pulling THE fly out of your box and having the point snap off.

If you get cement in the fly eye, clean it out while it's still in the vise; trying to do that on-stream at dusk, with a caddis hatch coming off and the trout going crazy will just led you to use some of the same colorful language you did when you tried to de-barb the fly.

Have a good background behind your vise - if you have one of those fancy profile plates, great; I just put a piece of cream 2mm foam against the base of my Ott light and it makes it so much easier on the eyes while tying (good lighting is huge, too).

Keep it short, keep it tight - too much thread off the bobbin and it's hard to control where you want the thread to go, too loose and stuff you tie down won't stay where you want it to.

Regards,
Scott