This topic has been on my mind for a while, especially since yesterday. In fact, as I plan on writing a movie review for my next post, you may end up reading that post before this one. No matter. It relates to reviews of all sorts.
Part of what sparked this was an absolutely horrible review of the film Les Miserables that can be found on CNN's website. I gave the reviewer and F, not because she panned the Golden Globe nominated film, but because of the content an nature of the review. Not every film is for everyone, but when you are in the business of writing a review, it needs to have information useful to those reading it. This particular review had nothing of use and really didn't say much besides showing that the reviewer hated the music the movie was based on and didn't seem to realize that was based on a classic book. There was little information on the quality of film making (be in writing, cinematography, set design, sound editing, film editing, singing caliber, acting quality, casting choices, or much else). The only thing that was clear was that she didn't like the musical and had judged the film based on that dislike and that she found Russell Crow's performance to be forced.
It is a perfect example of how NOT to write a review. Whether you are doing this professionally or because you have an opinion to share, you need to explain yourself in a manner that gets to the heart of what you like or don't like. For instance, I intensely dislike Star Trek: Generations. Why? Simple, the part of the story that revolves around Geordi and the hack of his visor throws 7 years of good writing for the series out the window. For someone who watched the TV series (the target audience for the film) it yanked you right out of the film. Yes, it was that bad. Those same tricks had been tried time and again in the series and the crew had detected them and performed as trained each time. It was like the crew had been replaced by fakes. Bad writing on one sub-plot destroyed an otherwise descent movie.
That is how you say way you disliked something. It needs to be specific and useful. A reader (or viewer if you make your review recommendations in video format) needs to come away from your review with information so they know if they are likely to agree with your review or disagree. Someone who has not watched the 7 seasons of Star Trek: The Next Generation isn't likely to be bothered by the same things that I was about Star Trek: Generations.
This holds true for book reviews. For independent authors, if you want the author to get something out of the review, you have to be specific. I've had a couple of reviews that comment that the book needs editing, but they don't say whether it is typos, grammar issues, or larger story issues. Is this person picky, or did I miss something obvious. I don't know from the general nature of the comment. Be specific. It might be something as simple as they don't like the dialect I write in, or it might be something as major as I used the wrong master document when I formatted it for upload.
Be specific, even if you are saying you liked it. What did you like? The reader of the review needs to know this for the review to be of any use. When reviewing a published book, you can give it a star rating to give your overall impression of it, but if you are going to take the time write something, give some details. Even something as simple as staying the story was enthralling says something. It means you were absorbed and there is a good chance the reader of your review will be as well. Don't say, "I liked it" or "I didn't like it" or "something just didn't work". If that is all you have to say, just give it the star rating or don't do anything.
That said, I have much to say about the film version of Les Miserables. And that is the criteria I use for when to write a review. If I just couldn't get into it and felt it just wasn't for me, that doesn't tell anyone anything, not unless you know exactly what I like and don't. Chances are the reader of a review isn't going to go out and check on all your likes and dislikes. If you become famous, that might be enough, but most reviewers aren't famous and never will be. Give the details and make your review something of value. A book can be well written and in need of proof-reading or it can be a good story that needs some editing to bring it out. Or maybe the movie you saw was well acted but poorly written (though sometimes it is hard to see that like the horror that is Highlander 2).
Give the reader something to go on, something to let them know if your review is useful to them or not. That is how to write a good review.