Hope someone here who's got knowledge about lawn care could help me.

We just laid a new turf in our garden about 5 months ago, it was healthy and green but now seems that there are parts of my grass are turning brown, dry or dying. I'm always trying my best to look after it watering,fertilising once a month, keeping not to be too much traffic on it, etc. I don't have idea now what went wrong.

The thing I've done at the moment was I have patch the few dead lawn with the lawn seeds with compost and they are seems growing fine but Im still worried because there are signs of my few lawns are drying or turning brown.