What are the guidelines for reviewing?
What should one avoid doing when reviewing?
How can it happen to be banned and what are the implications of this?
If I've been banned from review, where can I see the reason why?
The site offers several review queues that make helping to moderate this community more streamlined. For details on these queues see What are the review queues, and how do they work?.
When you decide to review please do it in that spirit of helping to moderate this community.
Do not turn it into a game or a competition. Yes, there are badges, stats, and leader-boards but don't make performing well there your objective. While it might seem harmless, empirically it is very hard to avoid negative effects on the quality of reviewing and it can create conflicts.
Do not rush it. Some care should be taken when evaluating posts for review. Yes, if one is used to doing it some posts can be evaluate quickly, but still please be diligent.
Reviews should be conducted in line with MSE's community standards. This means you should not (a) ignore rules or guidelines for questions you like, or (b) close questions that you dislike, but do not violate any rules or guidelines. For example, if you consistently vote to leave open questions with insufficient context, your review privileges will be revoked. On the other hand, if you consistently vote to close questions simply for being low level, your review privileges will be revoked.
On the site itself there is more leeway but in the review queue please try to take a middle of the road position. If you don't want to do this, or don't know what this is supposed to mean, that's not a problem, there is no obligation to review.
Review with an open mind. Go to the queue in the spirit of making a good faith effort to evaluate posts that are presented to you. Of course, it is alright and can even be desirable to narrow down the posts via the filtering-options and to skip posts one does not feel comfortable reviewing or where one does not know what to do. However, do not skip through the queue just to find one specific post you want to review. You also should note side-step casting votes for 'ideological' reasons via skipping posts. For example, if you do close-votes reviews and you go there with the idea to definitely only cast votes to close or to definitely only cast votes to leave open, then this is not really in the spirit of the review queues.
Failure to comply with these guidelines can result in a review-ban. You then will be blocked from reviewing for a certain period of time. Other than that the site can be used normally, this is not an account-suspension.
The decisions to review-ban are made by the moderators. We have a set of indicators and thresholds, and discuss it in cases of doubt. As any moderator action, these decisions can be questioned.
Finally, in the case that you have been banned from review, please note that you can see the reason by new-tab clicking the review queue icon in the top bar. (The necessity of this is due to a bug described here.)