Take advantage of the dry weather by painting fences, sheds and other wooden features with a preservative. Check that any products used are within their use-by date, and still legal. Many of the old oil-based products such as creosote are no longer approved for domestic use.
Clean up patios and hard surfaces to get rid of moss and algae. Doing this job now will prevent them becoming slippery during the winter.
Replace broken glass panes in greenhouses and fix leaking shed roofs before the autumn rains. Greenhouse guttering can also be checked to ensure it is not blocked with debris.