Everyone has their different opionions on what type of lube to use. And that's O.K. basically you want something that lubes and protects from rust. While at the same time doesn't attract too much pocket lint, dust, dirt, ect.
I used to use sentry solutions tuff cloth, but was never really impressed with it. I now use a product called eezox. It is superior in many aspects including rust resistance in my personal tests. A simple search here or on google will get you there. Even though you may not need to lube the blade, it doesn't hurt to do so. just use a thin even coat. Or follow the directions if using eezox. And a very small amount on both sides of the pivot of your knife every once in a while. It really depends on how much you use your knife, as to how often you should lube. The good news is that unlike firearms, you can't really damage a knife by over lubing it.
Later,
Jeff