hayden,
I did a large section of lawn last year and it came in beautiful.
1) I tilled in the fall
2) I tilled again after spring green up
3) I fertilized
4) I raked and smoothed (with then rented tractor)
5) I then seeded setting the spreader to 25% of recommended setting, I did vertical and horozontal passes and finished with diagonals, I achieved a very even spread with no hint of rowing etc.
6) I drove drove 5' of 3/4" ;pvc in the ground approximately 90' in between I was able to cover with 3 pipes, I then pushed the cheapo plastic oscillating stake sprinklers into each pipe and connected with garden hose, I ran every day for first 2 weeks, 3 times a week for the next 2 weeks, and weekly for the rest of the summer, water is the secret to great lawn, I watered even when there were light rains only deferring to steady rain over hours.
ps. the standard submersible 4" 10 gpm pump can only handle 2 to 4 sprinklers at a time.
I now have walking tractor style sprinkler which appears to work well in my limited experience with it, but I am worried as to what my happen when it drags the hose across new seedlings.
I beleive Tilling in fall and spring could be replaced with roundup in fall and spring. In my area snow covered the dirt yard for most of this time.
good luck and remember sand/clay will grow reasonable grass with enough water and fertilizer.
bruce