I'm a member of many sites, most of whose fields I am not an expert in. Even as a beginner, I find it very easy to determine what is a good question.
The implicit criteria I use is:
- Is it concise?
- Does it give all the required information?
- Is it generalizable?
And often, as a non-expert, I land on the page because I had the same question, so I feel even more comfortable saying that it's a useful question.
As for answers, I tend to avoid voting on them because it takes an expert's knowledge to determine the merits of different answers.
For example, in this question, someone who was more expert than the average voter had to take the drastic step of making a comment telling everyone to ignore the first few (most highly voted) answers.
Would it help Stack Exchange if this behavior was enforced by setting higher threshold on the privilege to vote on an answer? Perhaps even above the 101 free reputation a reputable SE user gets when joining a new site.