How can I avoid my knife from "dragging" across my unbaked bread when making slashes to let steam escape while baking? My slashes seem to be OK (not great) before I put the bread in the oven but never really open up during baking.  I'm thinking the slashes aren't deep enough but since I use a no knead method, I'm reluctant to press any harder.

Is there a trick to help the knife move more easily?  I use a serrated knife.
Professional bakers use straight razors. Chances are they are sharper than your knife, and easier to keep that way (or cheaper to replace, at least).

Also: wet the blade before making slashes. This helps lubricate the blade as it cuts, and keeps the cut bread from sticking.