Manual trans has balky shifting, what can I do?

[masospaghetti]

I don't expect the shifts to be as crisp as a Corvette's or a Civic's, but the stick often snags going into gear, especially third...it often grabs as I put it in third as well. The shifting just doesn't feel very good either compared to any of my other vehicles (1985 Corolla, 1986 CRX, 1989 CRX, 1989 Civic, 2003 Civic) that i've driven. I changed the fluid and put Mobil 1 synthetic ATF in there, didn't seem to change much.

Is there anything I can do to make shifting better? Any ATF additives, different ATF fluids, anything short of digging into the transmission itself?

vehicle is a 2000 Explorer Sport, OHV engine, 96,100 miles.

Thanks,
-J