Ideally, your home will be gorgeous before it goes on the market--fresh paint, cleaned windows and drapes, spotless floors and carpets, fresh flowers on the table, every detail attended to. Will you get more money for your home than a similar but less-attractive home down the street? Not much more.
A home's value is mostly based on its features--location, size, number of bedrooms and baths, garage, style, age, etc.--and what that combination of features is worth in a particular neighborhood. The reason for making your home cosmetically attractive is not to increase its value, but to sell it quickly. If yours looks better than the competition's, you'll get the first offers.
Now paint that house, cut that grass or rake those leaves and then go vote.