1. Scarify it.
2. Loosen soil or use new sandy stuff like Carlos.
3. Firm soil to stop settling later.
4. Rake lightly.
5. Seed at recommended rate.
6. Rake lightly and water on lightly if necessary to stop seed drying out.
7. Wait and chase off fucking pigeons. Shoot cats taking a dump.
8. Once sprouting ensure watering if dry weather.
9. Once around 3 inches roll it, then after a couple of days, cut it. Only a light cut. Never remove more than a third of its length.
10. Do not use any lawn weed treatment in the first few months. If must establish first. Manually remove any weeds
11. Use suitable feed. If using granular do not use on wet grass especially in warm weather, it may scorch.
12. Don't cut your grass too short like 90% of the population. Goes yellow, week and stresses.