I don't know about the grass you're using or your growing conditions, but I can tell you my experience w/ growing grass. First, if possible, soak the grass seed in water overnight before planting -- it makes it sprout so much quicker! but it is a pain dealing with the wet seed. :) Otherwise, be sure to keep it well-watered until it gets growing. Up here that means to water it every day. In your location you may need to water more frequently...

A few years ago I had a patch of lawn dug up by the water company, leaving me a big bare spot. I went to a local hardware store and bought a roll of bulk burlap. I seeded the area then cut the burlap to roughly fit the spot and laid it over the seed and watered it in. The burlap helped keep the birds away, helped keep the seed moist and in place, and once the grass got growing it was hard to find. No need to remove the burlap -- it just composts away! The water company guys came back to repair the bare spot long after I already had the new grass growing and they were fascinated by my burlap fix. :) Just make sure you get natural burlap and not some synthetic knockoff.

Here's a link to the stuff I used: Natural burlap.

Another vote for burlap, although I do remove it after the grass is growing good. It's reusable too. Home Depot sells burlap.