In what areas do you see overvalue of intelligence relative to practice and why do you think there really is overvalue in those areas?

I should probably note that my overvaluing of intelligence is more of an alief than a belief. Mostly it shows up if I'm unable to master (or at least get a basic proficiency in) a topic as fast as I'd like to. For instance, on some types of math problems I get quickly demotivated and feel that I'm not smart enough for them, when the actual problem is that I haven't had enough practice on them. This is despite the intellectual knowledge that I could master them, if I just had a bit more practice.

I've noticed for example that people's abilities to make good comments on LW do not seem to improve much with practice and feedback from votes (beyond maybe the first few weeks or so). Does this view represent an overvalue of intelligence?

That sounds about right, though I would note that there's a huge amount of background knowledge that you need to absorb on LW. Not just raw facts, either, but ways of thinking. The lack of improvement might partially be because some people have absorbed that knowledge when they start posting and some haven't, and absorbing it takes such a long time that the improvement happens too slowly to notice.