Seeded lawn last October - Need advice
 

I tilled and seeded my new yard last October before it froze (midwest
- central Illinois). I threw down some straw in the dry areas, and I
had what looked to have been a good start last fall...lots of green
grass coming up in areas.

Now it's March, and I'm wondering when I a good time is to start
seeding again. What are good products to use? Do I need to till the
bare areas? My dirt is not real hard, but it's not tilled anymore.
Plus, I have quite a few bare or thin areas.

Thanks
Mike