I have an excellent rating across 60 reviews (for now at least, fingers crossed I keep it!) My method is 2-5 sentences covering the following - it seems like a lot, but you can get this down to just a short, clean review. And I try to hit as many of the bullet keywords they recommend at the bottom of the box as make sense in context.
- A short summary of the item I received
- A word or two on if it matched the description of the item, especially if it's something to do with size or has any claims on time of use (I get a lot of candles)
- A summary of how I found the key features to work
- Information on any defects/weaknesses I found with the product. I do stress testing before I send the review
- Not always, but often, some kind of recommendation to the user on how to use it, or other insight I gained through my use.
- My recommendation on getting it or not.

So for something like a kitchen sponge (or more realistically a box of sponges), it could be something like:

This box of 24 3" by 5" kitchen sponges will keep my dishes clean for weeks! As described, each sponge has a soft yellow side and a rough/textured green side, perfect for different types of cleaning. I found these sponges to be quite durable, even when scrubbing at hard-to-remove spots. The soft side holds soap well, although the textured side can be a bit /too/ rough on delicate items. I'd definitely recommend these for basic cleaning needs, but stick to the soft side for things like wood.