I don't know about how you prepare for posting a review, but I have to get into the 'zone' so to speak. I try not to post when I'm sitting in the park. Learned to give things a day or two.
However, once I've got all my ducks in a row (price we paid, and specific notes from our experiences), I generally read the other reviews from that park first. Also, refresh myself with that park's website.
Then I try to outline what we found, or experienced, (without making it a travel blog), in order to help the next person make a key decision.
I am generally the co-pilot on our travels. I am reading YOUR review, in advance, in order to determine whether I can direct my DH and pilot, into this campground/park, or not.
Are the sites long enough to pull in overnight? Are there ANY amenities, or do I need to prep to boondock for the night? For heavens sake, did you find the electricity MISWIRED ???
Are the surroundings such that we could stay a while, or do we need to shower, sleep and bolt down a cup of coffee before hitting the road quickly the next morning?
Can a dog be walked without harrassment?
Is it a destination park, or a destination area?
Was there entertainment for children...how about adults?
Were you treated with respect at check-in?
That's what I'm looking for when I look at reviews.
I skip over the " We had a good time, we will be back" I'm glad, but no help.