You only have one chance to make a good first impression so the street appeal of your home is the first thing a potential buyer will see.
If the house looks unattractive on the outside, prospective buyers will assume it is unattractive on the inside as well.
A few simple ways to improve the street appeal of your home is to spend a few hundred dollars on beautifying your gardens, touching up and repainting your gutters and down pipes and removing any rubbish.
Repaint the interior if it is looking tired and dated but use neutral colours that will appeal to a broad cross-section of the market. Replace handles and knobs on drawers and cupboards. Make sure the house is spotless and remove all clutter.