I typically try to follow the rules as posted, as long as it's safest for everyone.
I tend to avoid SIDEWALKS as possible, since it's usually faster and smoother on a street surface. However, here in the suburbs, there are a lot of 4 and 6-lane 'arterial' roads with 45mph limit (55mph operating speed) and curbs on both sides. The speed and volume of traffic and lack of an 'out' on these roads does not permit reasonably safe cycling except in the wee hours of the morning, so I ride the sidewalks there. Typically pedestrian traffic is very low on these roads so it's not a big deal.
If I am on a sidewalk, I will slow and yield the pavement to oncoming pedestrians. I use a bell when overtaking pedestrians (or the occasional rider) I also give as much room as possible. If the road's clear, I 'll jump the curb, and overtake in the traffic lane, and get back to the sidewalk at the end of the block.
If I'm riding in the street, I am cognizant of the fact that my speed is 10-20mph slower than the operating speed of that road, and try to keep as far right as reasonable. I don't use mirrors much, but I can hear if there's a car back, and can do a shoulder-check without swerving in to the lane. I try to hold up car traffic as little as possible; if there's a wide spot, I'll use it, and 'wave up' the cars behind me to pass. I find that if you acknowledge the cars behind you, they will be a little more patient and give you more room when they do pass.
It's all about making things as smooth as possible for everyone.