[Raven]

if you have any willow trees near you ....you can take like 50 cuttings....say
20 inches long and let them soak in a five gallon bucket full of water...for a week....the cuttings will release their own growth hormone rooting agent into the water and that will increase your root growth one hundred times.....

or you can "buy" a product called super thrive (pricey stuff) which is a vitamin b1 suppliment
only one drop makes a gallon of "mix"...or "super thrive water" and that will increase root growth 100 times...theres a venturi style mixing valve sold that can siphon out of a 5 gallon bucket before your sprinkling hose or sprinkler so you can fertilize or root stimulate as you water.

grass seed grows best when it has firm contact with the soil....so i second the idea of using a rented roller... where as most people have the grass seed laying on the surface after the first rain exposes it...and then let it dry out. an automatic watering timer - is a great thing to have!