Writing.Com 101

be honest.
Helping writers improve their craft is the mission of Writing.Com. Honest opinions are what help writers improve. Giving false feedback doesn't help anyone and can lead an author down a long road to bitter disappointment.

be encouraging.
Writing.Com is a site for writers of all ages and skill levels. Everyone at every level should be encouraged to continue writing! Encouraging reviews are more likely to be used by an author which means the time creating the review was well spent. Whether the author decides to use the reviewer's honest suggestions or not, the review should be motivating and encourage the author to keep writing

be respectful.
Regardless of an author's level of skill or talent, a reviewer should always respect that the author is an individual person. A reviewer flaunting that they are better than the author they're reviewing is not respectful and is counterproductive.

be well-rounded.
While honesty is very important, a review that points out only flaws without any mention of an item's positive points is not nearly as helpful to an author as a well-rounded review with both positive and negative remarks. Don't forget, the same goes for reviews that only point out positives! Even the greatest pieces of writing have room for suggestions and opinions.

match the rating.
If you're sending a review full of corrections, it's important to consider that with your star rating selection. 5.0s shouldn't need any corrections. On the other extreme, a 1.0 should have endless errors and you couldn't possibly list them all. Offering to return and re-rate the item after a round of updates makes it more likely your suggestions will be considered.

be visually appealing and easy to understand.
When reviewing, presentation is very important. Use WritingML to make corrections stand out or quote small portions 1 of the work. Emoticons can highlight important points in the review and can be creatively used to make the review feel more friendly. Double-spaced paragraphs and other appropriate spacing makes reading a review much easier on the eyes. Remember: Too much WritingML can ruin your review; use it in moderation!

How did the writing make you feel? Did it invoke any emotions?
Can you relate to the writing through a personal experience?
Did the plot interest you? Were the characters believable? Did the dialog flow naturally?
Did the time, place and other setting characteristics work together?
What did you like most? What did you like least? Did anything stand out?
Is there anything you would change within the writing?
Was the writing memorable? Why or why not?
If this were your own writing, what would you want to know from a reviewer?