Part the RPG author racket is learning to grow a thick skin. For every great fan that compliments your work or happily asks if you'll autograph a book, there is also the flip side: harsh online critiques, reviewers with egos roughly the size of Brazil, and arm-chair critics quick to make uninformed assumptions or make insulting comments about your work. (Recently a reviewer made the assertion that I don't know the location of Scotland and England—two countries in which I spent months—apparently based solely on the fact that I used the word "glen" [a word that has long since evolved from its Scottish roots into the popular lexicon] to describe something in England. Big sigh.) This goes with the territory for any writer, be you Ed Greenwood or Stephen King.
I've always taken the good and the bad. Sometimes the bad still stings my pride, but it doesn't diminish the feeling I get when someone gets pleasure out of something I've written. Not even close. Attending this year's Gen Con was a good reminder just how many cool, intelligent people have taken the time to read my work, and for that I'm incredibly grateful.
That said, I humbly (but with a touch of sarcasm perhaps) offer up some dos and don'ts for prospective reviewers:
Don't ask a product to be more than it is. An adventure isn't a sourcebook or setting. Likewise, a sourcebook may contain only limited adventure material. We'd all like to get everything in every product (me too!), but such is life.
Don't assume the author has much input into the art, ad copy, product's title, or line design—they usually do not.
Don't assume intent of the author. Likewise, don't make the assertion the author did no research or rushed a product because you've discovered a mistake. Most all RPG authors do it for love of the craft, not the money, and every author I've met cares deeply about the product they put out. Remember also that most RPG authors are freelancers, writing on a hard deadline around a separate full-time career, family, and the other things that fill all our lives.
This brings to mind a true story. When my first adventure was published in Dungeon magazine back in 1997, one of the adventure handouts contained not one, not two, but three mistakes. (The handout in question was a short note to be found by the PCs.) I noticed this when my issue advances arrived. I hurriedly checked my original graphic, but it was fine—apparently the typesetter keyed in the text incorrectly. (A common error, which I have certainly done myself.) I contacted the editor and they decided to run errata in the next issue ... hooray! Dungeon rarely did this, so I counted my blessings ... until the correction graphic appeared in the next issue, containing yet another error. The moral: mistakes happen.
Don't allow your biases to get in the way. If you are biased against the game system, game edition, the company, the author or editor of a product, or the nationality of the author/editor, exclude yourself. You cannot write a objective review.
Likewise, do not allow your previous experiences with a company or product line to influence your review—judge the product on its own merits. (It's fair to refer to the overall quality of a line or company's releases in a review, but one should not show any bias toward the specific product being reviewed.)
Don't assume the play style of your readers matches yours. Not every D&D player prefers hack & slash -style play, not every Shadowrun player likes lots of net-hacking, and not every Call of Cthulhu player prefers a super-historic scenario over pulp-style play. Likewise, don't assume a GM purchasing a product is of your age or experience level; a customer can be a 14-year-old newbie or a 50-year-old veteran.
Don't say that an adventure could be better with a bit of tweaking. All adventures, even those written by Gygax, are very very rarely played exactly as written. Every GM has a unique style and will run things a bit different, so there's no need to state the obvious unless major changes are absolutely necessary to fill plot gaps and the like.
Do run an adventure for players before you review it. Writing a complete review based on a single read-through alone is rather like reviewing a film based on the screenplay, yet a huge number of reviewers still do this.
Do be fair. Acknowledge the good and the bad, and write to inform rather than as a mere exercise of sardonic wit.
Do know that authors very much appreciate you taking the time to write a review of their work! Reviews, fairly written, help the author hone his or her craft. I thank all those that take the time to write RPG reviews.