How to do a Review

In this day and age, everyone and their grandmother are 'critics'/ 'reviewers'. An editor of a publication, however, might not think so. Here's a list of suggestions to hone your reviewing skills:

Read/view/listen to the thing
When you are about to review something, make sure you have substantial knowledge about it. If you are critiquing a book, read it cover to cover, if you are doing a movie, watch it attentively; if it's an album, listen to it with the utmost concentration, more than once.

Take notes
Always do that. It helps a lot. A book or a movie can be long and you might forget some crucial opinion you made if you don't keep track of it. When you are done, you can read over these notes and form your general opinion of it. It'll help you outline the review.

Decide on the tone
Ask yourself whether the book you read, or the movie you watched was worth it. Did you like it, or hate it, or have mixed feelings about it? If you liked it, makes sure to let your review give off a positive tone. The whole point of the review is for you to let the readers know “what you thought of it”.

Get the basic facts right
When you are doing a review, you have to state primary facts like the publication year/ the author's name/ the director's name/ the music label. Make sure you get these correct. Incorrect facts will act detrimental to your review and make the reader doubt your critiquing capability. Never let the reader doubt your critiquing capability.

Set up a balanced structure
Keep everything balanced: the introductory info, the summary, the exfoliation of the “themes”, your two cents on it, whether the thing in question is worth the reader's time and money or not. Don't write a one sentence summary and then follow it up with a 200 word exposition on one of the themes. It would read awkwardly.

Keep the synopsis short and concise
When doing a review you have to talk about the story. That's a must. But don't drawl on and on about what is happening the whole time. Give the reader only the necessary details. They don't need to know the entire story.

Back your assessment with evidence
For example, if you think the movie you are reviewing was terrible, tell the reader why is was so. Give evidence. Don't just say, “I think it was terrible.” Say, “the acting was sloppy, the story pretentious, the characters one sided, and hence I found it terrible.”
Give examples. If you think a scene was implausible, then tell the reader about the scene and precisely what were in those scenes that made the whole thing implausible.

Don't digress on unnecessary matters
An annoying thing several reviewers do is compare the thing they are reviewing with the artist's other works (which is perfectly fine) and then proceed to talk about the artist's “other works” at length (which isn't fine).
Same goes for adaptations. Don't dwell much on the book if you are reviewing the movie adapted from that book.

Don't give away the ending
Like, never.