You know, I haven't been yelled at or belittled on rotations. Yeah, I've been corrected - but never in a rude or demeaning way. I do know other students that have been belittled, yelled at, etc., etc. (one attending called a student a 'fluffer' recently).
What I have found best to avoid getting yelled at -- read, look things up, be proactive. If someone does yell at you or belittle you - don't take it personally. Learn from it and move on.
If you don't know something - there can be a couple of different types of attendings and residents. Those that want you to attempt to reason through and come up with an answer; and those that would rather you say "I don't know, but I will look it up". Don't expect them to tell you the answers, and if you say you are going to look something up, do it, and in a timely manner.
My evals have always paralleled what I was being told verbally. If I needed to improve in an area, and was told about it, my evals reflected that. If I was doing well in an area, my evals reflected that.
I thought I was just lucky, except I've worked with some preceptors I have been told can be hard on students (though, never the one that called a student a fluffer, it's my understanding that it doesn't matter what you do, he will belittle you at some point during your rotation with him).