Ride in the middle of the road when need be. Aggressive drivers can of course make this annoying. A rearview mirror (reminds me I need to replace mine after it broke) is helpful for keeping an eye on potential threatening ones. Make sure of course you are visible, at night I usually wear a reflective vest in the crappy weather, plus a bright taillight on the bike and one on the helmet too.
I often find turning my head and looking at them seems to calm them down a little bit, as if they forget there is a human there. Pointing to the snowy/icy bank and shrugging? If I see a spot where I can move over to help facilitate passing I'll do that as well since it just makes life go smoother.
Picking a route with multilanes is best because drivers can easily pass you. On a narrower street, I've had an aggressive driver drive up over a snowbank, on to the sidewalk (totally spraying me with slush by the way) in order to get to the stop sign at the end of the street a second or two faster.