Mow less frequently during autumn, and raise the height of cut as the growth rate of the grass slows down. This will help the lawn to withstand the last of the warm, dry weather, and also keep it resistant to treading as the wet weather arrives.
You can harden your lawn up for winter by applying an autumn lawn feed, which is high in potassium. Do this after scarifying and aerating but before applying a top dressing. Do not give summer feeds that are high in nitrogen as this will only result in weak, soft growth, which will be prone to disease in the autumn weather.
Loam and sand top dressings are usually applied at a rate of 2kg per sq m (4.5lb per sq yd), working them into the lawn with a stiff brush or the back of a garden rake. If the proprietary product you use has specific application instructions, then do follow these closely.
This is an ideal time of year to create new lawns from turf or seed.
Rectify summer damage by repairing a patchy lawn with turf or seed.
Any brown patches caused by drought will quickly green up by themselves when the rain comes and the temperatures fall - usually towards the end of the month.
Good autumn lawn care will do much towards solving patches caused by problems such as fungi (e.g. fairy rings), moss and weeds. These problems usually develop on lawns that are already weakened by poor conditions - waterlogging, drought and compaction, for example.