If you are serious about lawn turf (which I'm not), there is enough to learn to sustain a three-hour class.
Most people haven't a clue how may square feet are in their yard and how to calculate how much fertilizer to use - and so they use two to three times more than they need. Any nitrogen not taken up by the grass becomes runoff that, in a city, gets flushed into the storm drain. In the country, it washes into the water table.
Master Gardener Eddie Wharton is the king of compost. Have a composting question? Ask me. I'll ask Eddie!
Credit: This graphic is from organicgardeninginfo.com