1) No spoilers
2) Your personal opinions about the genre (I hate shooters, so this game automatically sucks!) should be kept to a minimum
3) Concentrate on reviewing the game and every aspect of it; Pretend you're trying to show someone with no game experience what the game is about
4) If a game is a sequel, then you may draw comparisons to its prequel, but only with things like new additions, things removed and improvements
4a) I really don't think a game should be compared to another, even if they are really similar in nature (God of War and Dante's Inferno, as an example)
5) Personally, I like the structure system better, since I can go straight to the gameplay section and read about that, without worrying about anything else

As far as the second point, I can see it both ways. By giving some background, you can build some credibility, especially among fans. It can also help build more of a connection with the reader as well.

There are two reasons I personally don't care for it though. First, I really want the review to be as concise as possible. The less reading I have to do, the better. Given that there is a finite amount of time in the day, I generally don't want to spend much time reading a review (I would rather spend the time playing the game for example). Second, on a personal level, it doesn't add much to the review. I think reviews should be judged on their own merit, and not on the past playing history of the reviewer. In addition, the game being reviewed should be the main focus throughout the review (kind of goes back to being concise).

As I said, I can see it going both ways, and you would probably need more responses to get an idea about what readers really want. Also, I think your spot on with Resistance and Resistance 2. I haven't played the third one yet though. I think there solid games-first one more than the second, but they aren't exceptional.

If a reviewer doesn't like a particular genre, for eg I am not so much enthusiastic about fighting games. Then I should avoid reviewing fighting games because then it wouldn't be objective. However if you are to force yourself to review a genre that you don't like then you should review it like how you feel. Maybe be a little lenient on the said game since you are obviously going to be a little harsh naturally.

i would do reviewing but my English is horrible. But i say is structure your review to target the gamers you think would enjoy this game and write it around that. Finding what type of gamer would like it is the ticky part. But remember people are reading the review to see if they like it, so try and remove the parts about you liking it and what you wanted because your a reviewer and your opinion is far far different then that of the general reader.

Once you have found the type of group that would enjoy the game and made sure that group of gamers isn't yourself and your personal opinion dont control the review, then talk about Why they will like it and whats good, then talk about the problems that could make your dislike, then talk about what does this game offer to people who aren't interested in this game. And never use a score or star system, the score system is completely broken in the games industry so best to just stay away.

An example game would be say fifa, and this is easy to pick out the group that would like this game by saying sport fans but more narrow would be sport fans that enjoy soccer. Then you would go into how the game simulates soccer, what the social elements are because soccer is a social sport so the gamers would want to know what the game offers in terms of social gaming with others. Then you point out the lows like its a update verison that not much different to the last and there is no point upgraded etc.

But you can also mention like, if you like soccer but not sports game, fifa may float your boat and be the game to get you into the genre etc.

So overall my review structure is basically to narrow down who would like this game and tell them why they like it, then move onto the negatives then onto those on the outside because thats what your readers would want i say. The gamers who are into that type of game would read the review to see if it holds up as a good game in the genre and most likely going to get it unless the negatives out way to positives, and then you got people that maybe not a gamer in that genre that seen a trailer, interested but doesn't know if this is the game for me. Target those two groups and i would say the reviews would be good, unless you screw up who would like the game.

Lot's of great responses, guys. Keep it up.

I'm actually really surprised to see how many people prefer structured reviews as opposed to free-flowing reviews. I used to do them that way but was told it seems to sterile (I actually prefer structured reviews myself, but this site doesn't do them that way).

I'm also surprised how many people dislike hearing about the critic's backstory, I figured people would enjoy that.

Other than that I'm getting a lot of "be concise, get to the point, no dillydallying", which I'm all for. I could easily do most reviews in 500-1000 words if I'm not going for eloquence. So yeah, more responses, this is fun!

I remember when I was writing a lot of reviews on GameFAQs, whenever I used to get critiques about them, structured reviews were kind of looked down upon. I really don't see the point, other than the fact that it flows more freely. As I said before, I like structured reviews because you can just go to a section to read about that specific point rather than try to hunt that section down in a regular review.

Ok, these are my thoughts:

1-Is it okay to compare a game to another game, or should the references be vague? Only if the game reviewed is a sequel or the new entry of an existing franchise. In those cases comparisons between the new game and the old ones are welcome.

2-  Do you prefer the review to be free-flowing or structured? I don't care. The structures ones are good because you know what to expect from that part and you can skip it if you want. Free-flowing ones tend to be a bit more chaotic, but if well written are also more enjoyable.

3-What's the ideal length for a review? Do you like longer or shorter reviews? The necessary. If there is few to say then do a short one, if you have lots of thing to say, do it. Trying to stick with a certain lengh causes reviews to be boring (if longer than needed) or frustating (if shorter).

4-Do you care about the reviewer's story and how he came to play this game?   Actually not. It's ok if it's a sequel and the reviewer says that has played the other ones or not, but the story of what happend the first time he started the game, etc. it's pointless. At least to many

5-Do you prefer to laugh while reading a review, or would you prefer it to be serious? A review has to be entertaining. Besides there are not many games where a funny review would fit. I'd find odd to read a funny review of games such as Resident Evil or Gears of War.

6-Do you prefer a review that points out flaws or one that highlights the good? Is Balance best? Balance, ofc. Any game will have its pros and cons, so it's good to know which ones are.

7-Is it okay to use a review as a platform to discuss a game mechanic you feel strongly about? By "game mechanic", do you mean the controls or the way the game progresses? Either way, both things are needed as they can make or break a game.  

8-Do you prefer written or video/audio reviews. Since my english is quite bad, I prefer the written ones, but video-reviews are also useful as we can see the game.

9-Should it be about opinion or should it stick to the straight facts? Well, truth is that it will always be an opinion, as the review will express the experience of the reviewer. That said, and going against the 3rd point, you can write the review relying to the facts and add a "last comments" or "personal view" section at the end  when you can share your thoughts.

11-What is your ideal review grade? What does each number or letter mean to you? Do you prefer letter or number grading? See Jay520 post.

At the end of the day, what matters in a review is the message. If you can manage to explain why a game (or a movie, comic, whatever) is good or bad and why, then the review has done it's job.

Just my  2 cents.

when I talk about game mechanics, I'm talking about things that have gotten mainstream and are common, like how FPS games usually have regenerating health or most shooters in general have a lot of cover-based combat.  Perhaps I don't like RPG-styled turn based battle, or something.  

I'm not sure how I feel about inserting your opinion about a game mechanic. I would think maybe a quick sentence or two would be more than enough, like "This game utilizes the tired mechanic of regenerating health, that's been common in first-person shooters these days, which is kind of uninspiring and dull."