So I went from a 3 star to a 2 star rating. Isabelle says to put decorations around the island to increase. Anyone know hoe=w i can get it to a 5 star rating?

If you look at your map, you'll notice how your island is divided into squares. You'll need to put decorations into every one of the squares.

It's a very detailed process that I've not found any DEFINITE guide with the requirements for a 5 star town. I suggest just searching for a guide via google to find some clue/suggestions.

Sorry I couldnt be of more help :-/

Your whole island needs to practically be covered.
Build fences, put down outdoor furniture, pick up all of your weeds, sticks and dig up all fossils, plant flowers.
Just make your town full of fun stuff and it'll go up!
I just spent a lot of time building fences and putting down shrubs and flowers and it rose from a 3 to a 4 star!
It takes a lot of time

I just put a ton of fish outside because I ran out of room in my house. Isabelle loved it and gave me 5 stars.

So, basically, according to my personal experience, and contrary to popular belief, Isabelle is not saying you MUST do what she suggests; she's just sayin'. So if she says "Hey, we can make the island look nice by placing fences!", the important part isn't the fences, but the "place down some stuff" part.

Just pile a ton of fish, bugs, clothes, or furniture in a corner and craft log stumps (or something like that. any table works since it's 2 pieces of furniture in one tile) and put stuff on top of them, then plant a ton of flowers. I emptied my house of all the fish I was going to sell and set them outside, which got me up to 5 stars. I also set up some fences with no space to walk through them, which the tourists absolutely adored for some reason.