The secret to a great sear is to have a fairly
hot (not
scalding), dry (preferably cast iron)
pan; rub some oil, salt, and pepper on the meat you're searing (this works particularly well with ahi); and lay it in the
pan.
I read a lot about this: some women use thermometers to make sure they got it
hot enough, but my lactation consultant told me just
scald it until bubbles start to form around the edge of the
pan.