Interestingly, it doesn't seem like all blades are created equal.
The sharpest seem to be "Feather" or "Sharks" from what I can tell. I ordered some of both. The Feathers aren't here yet, but the Sharks are very sharp. Maybe too sharp for me. I'm still trying to figure it out.
I started with Dorco blades, which are less aggressive, and I tend to like them. So much that I bought one hundred (for $6).
You can buy blade sample packs and try different ones. Everyone likes something different, I guess.
I started with two passes, but sometimes do three if everything is working and I don't seem to be getting any irritation.