I reseeded the entire lawn here last year and it was a big success, except for a couple small spots. Used Kentucky Blue grass and 5 cubic yards of triple mix...really good rich dark soil. That amount of soil covered the ~3000 sq. feet of yard I have.
To me the key was spreading the triple mix pretty thick (an inch+), then sprinkling VERY liberally lots of seed, then covering the seed again with a thin layer of dirt (maybe a quarter inch this time). The last part is important so that the seed doesn't blow away or get eaten by birds.
And of course, lots of water. Prior to last year I basically had dirt, not a lawn. Now I'd say it's 95% thick lawn. Oh, and weeds this year as an added bonus.