Good advice Stephen, I was watching Master Chef Professional a few days ago and Michel Roux Jr. said that it's better to plate things in 3's as it has a better visual appeal to us.
I find it hard to make the food on my plates look like that of great chef, so am struggling to find anything to offer in way if advice. I would say though, the ratio of food on the plate is quite important. Too much food on the plate and you will never make it look like art, less is definitely more as CH mentions.