All the path following steering algorithms (e.g. for robots steering to follow a colored terrain) that I can find are predictive, so they rely on the robot being able to sense some distance beyond its body. I need path following behavior on a robot with a light sensor on its underside. It can only see terrain it is directly over and so can't make any predictions; are there any standard examples of good techniques to use for this?
I think that the technique you are looking for will most likely depend on what environment will you be operating in as well as to what type of your resources will your robot have access to. I have used NXT robots in the past, so you might consider this video interesting (This video is not mine).
Assuming that you will be working on a flat non glossy surface, you can let your robot wander around until it finds a predefined colour. The robot can then kick in a 'path following' mechanism and will keep tracking the line. If it does not sense the line any more, it might want to try to turn right and/or left (since the line might no longer be under the robot because it has found a bend).
In this case though the robot will need in advance what is the colour of the line that it needs to follow.