Does it convey what you are selling? Colors and placement of text and graphics play an important role in giving your web site visitors a comfort level for wanting to know more about your product and/or service and wanting to do business with you.
Keep it simple and easy to read unless you have something new, exciting or revolutionary? Bold & vibrant is OK when used in moderation.
If you are selling a Professional Service, does the web site convey trust, confidence and stability?
If you have a unique product include photos, descriptions, prices and why a customer should buy Your product from You.