Firewood should be neatly stacked away from the house. Barbecue grills should be cleaned. Attach all down spouts to gutters and paint, if needed. Any loose shingles, tiles, etc. should be secured or repaired. Paint the front, back, and side entrance doors.
Nothing looks worse than a pealing door.
Ensure the mailbox is in good condition. If you are neither prepared to nor want to spend hundreds of dollars for exterior painting, be prepared to make an immediate and substantial price reduction. Re-point chimneys and brick or stone work if needed. Keep receipts and warranties. You may have chuckled or frowned or worse when reading this list.