I try to avoid merging to the right (in US, left in UK). If I'm approaching a spot where a road narrows from, say, two lanes on my side to one, I try to be in the lane which continues instead of the one which must merge. If I'm not sure which lane that is, I try to be in the right lane so that if I do have to merge, I don't have to depend on my far-side mirror.

I also try to avoid driving directly beside other cars on open freeways, particularly large trucks and idiots driving slowly in the fast lane. The nearest I've ever come to a truly major collision was due to someone apparently realizing they were driving slowly in the fast lane and deciding to move over while I was beside them. I now assume that if someone is not sufficiently awake and aware to drive in the correct lane, there's a good chance they're not going to check their mirror before moving over.