Rake up fallen leaves and add them to your compost box or shred them with your lawn mower and spread them around in garden beds, under hedges and around trees and shrubs (add organic matter as the leaves decompose).
Finish planting spring bulbs. Plant them where they will have good drainage. Cover clumps of Tulips and Crocus with chicken wire to discourage squirrels.
Lime your lawn with Dolopril lime; apply a few handfuls around lilac bushes as well.
Lift, divide and replant spring and summer blooming perennials if they are getting crowded.
Order seed catalogues for next year!