Just try to follow what other people have done, that'll normally be the right way.
DON'T edit anybody else's review unless it is for spelling, grammar, formatting etc. If you have differing views, make a new page with a different title with your username in it (“vault:[category]:[manufacturer]:[product]:[username]:review:”).
A format similar to Harmony Central is suggested. Here is what they say:
BE CRITICAL! Nothing is perfect. Superficial, glowing reviews may not get published.
Resist the new product rush! Take some time and really work with the product. If you need to comment right away, make it clear you haven't used it extensively.
Please include some of the specs too, since not everyone will know the model numbers and names alone.
For manufacturers - We value your input, but DO NOT pose as a customer.
====== [name] ======
needs finishing
===== Summary =====
* Blah: x/10
* Overall: x/10
====== [name] ======
needs finishing
===== Summary =====
* Blah: x/10
* Overall: x/10
====== [name] ======
needs finishing
===== Summary =====
* Blah: x/10
* Overall: x/10
====== [name] ======
===== Specs =====
===== Reviews =====
===== Sound Samples =====
===== External Links =====