As temperatures sadly start dropping away, and nights draw in, there is a likelihood of first frosts so do take action to move your Summer tender plants and bulbs into containers and ideally place them into a porch or conservatory which may have some heating during winter. Bubble wrap containers if possible, it works well.
Clear falling leaves from the lawn; if possible store some in bags with holes in and tie up to produce valuable leaf mould.
Remove detritus, dead, dying and diseased matter as these are perfect habitats for over wintering pathogens including viruses. Infected material such as rose black spot leaves should be burnt, not composted. Kitchen/vegetable gardens need a very thorough clear-out to give the soil a rest.
Reduce mowing frequency and allow grass a little more height over winter to strengthen against moss and weeds. Scarifying and top dressing will pay dividends to your lawn for next summer by removing much more thatch than you will believe is nestling amongst the grass.
Cut back climbers. Divide perennials. Lift dahlias and store the tubers upside down in a cool dry wooden tray.
Prepare ground for planting shrubs and trees. Plant new hardy herbaceous perennials and bare root plants.
Plant spring bulbs now you will be well rewarded.
Enjoy the last remnants of Autumn colour in your garden and give yourself a pat on the back for all the hard work put in over the year.