Recently I've been thinking about how I handle situations in class where I'm not able to get a handle on the material very quickly - especially if I'm slower than others (that really exacerbates the issue). So firstly of course what the hell am I doing comparing myself to someone else? Their performance (esp at the stage of learning) is totally irrelevant. Secondly - I've begun to see how how one handles these situations is really important. You can't expect the learning process to always be smooth. Some classes are more challenging than others, and I just need to come up with strategies that help me take things in my stride.
So my first strategy is to remind myself that challenge can lead to growth. Whenever I really suck at something big time I think to myself: I'm about to improve so much, just as well as I get the hang of this. Focusing on how rewarding it's all going to be helps me keep my spirits up. It sure as heck beats thinking things like "Omg I really suck at this. I'm so rubbish I don't even know why I try" because that's how I ended up getting so frustrated I cried in class.
The second strategy is to think of the challenge as a "take-away" project. I might not be able to get the hang of it in an hour, but I will definitely be able to get the hang of it (or at least make significant improvements) if I spend some time working on the skill.
Given the previous strategy my next step is to set a goal for the duration of the class: If I try to do the rhythm in my feet AND the isolation in my torso AND the hand/arm gestures then I'll probably fail. So I'll just work on two of the three (and usually the feet is a good place to start because it presents the least trouble to me). The rule is generally to set a realistic goal that I can kind of achieve during the class - and then I'll be happy with myself and feel accomplish regardless.
Realistic expectations also matter though - no matter how I work on it I won't go back next week and do it as well as the teacher or someone else in my class. Physical skills take time to settle in, and there's no way to hurry that process. What matters is that I can feel my own progress (even though sometimes it feels like a bit of a stop and go rather than a smooth progression - I hear that's normal).
Also something that can be really frustrating is when I KNOW exactly what I need to do (such as in a polyrhythm exercise. what each hand is doing is pretty fucking easy. it gets near impossible when it put it together), but my body won't do it. That's when patience comes in.
Sometimes I get so frustrated I want to lop off the offending limb but then I usually get the hang of it later so I'm always glad that I didn't. The long-run. The big picture. You see?