If you have any moss problems you can take action now to eradicate it. Discourage moss by improving the drainage. Aerate the lawn and feed as necessary to keep the grass growing strongly. If the problem is serious you can use moss-killer chemicals, but allow the moss to turn brown before raking or scarifying, otherwise you will just spread the moss around your lawn. If you have only a small patch of lawn you can rake it by hand but if your lawn area is big one you might wish to invest in a powered lawn rake.
If you are using a part of your lawn as a short cut to a specific part of your garden or some parts of your lawn have been compacted through constant use from summer games or other activities, you can improve it now by aerating it. Spike small areas with a garden fork pushed at least 10-15 cm into the ground spacing the holes a few cm apart. Wiggle the fork into the ground backwards and forwards each time to open up the holes. For larger areas of compacted lawn you might wish to use a hollow-tined aerator that removes a core of soil efficiently. After aeration, brush a 50:50 mixture of sifted garden soil and sharp sand into the holes. If the soil is poorly drained, you can use only sand to fill the holes. This will improve the drainage and aeration in the surface of the lawn.
Usually, lawns do not need feeding in autumn, but if your lawn looks tired after excessive wear and tear during the summer you might wish to give it a boost now. Make sure you do not use a spring lawn feed as it contains too much nitrogen and this will encourage a lush and leafy growth that will be easy damaged by frost and is prone to diseases. For best results use a proprietary autumn lawn feed that will promote good root growth and tough top-growth that will help your lawn be strong over the winter.
Autumn is also a good time for weeding your lawn. Single weeds can be removed by hand using an old kitchen knife or a spot weedkiller. Make sure you remove the whole plant, the tap root as well as the top growth, when you remove each weed. If the weeds are more widespread then you should use a combined weedkiller and autumn feed product.
If you choose to have a wildflower meadow instead of a lawn than you should use autumn time to tidy it up. Wildflower meadows that contain summer-flowering plants will benefit now from a tidying up. Once the wildflowers have set seeds, use a scythe to cut the meadow back if you only have a small area, or hire a powered mechanical version for larger areas. Leave the cut material dry so that any seed has time to ripen and scatter before you gather up and place the trimmings in a compost bin for recycling.