Wipe down the blinds. Replace any broken or cracked windows or mirrors. In the winter, remove and store screens. In summer repair and wash screens. Call on yourself and pay special attention to how your front entrance looks.
First impressions make a big difference.
If it has been over a year since the carpets have been cleaned, do it now. Vinyl floors should be waxed or polished. Hardwood floors should be reconditioned if they need it. Light and bright is right. Replace burned out lights, put bulbs in every socket, keep shades and drapes open during the day.