Always use non abrasive cleansers on your solar panels. An abrasive cleaner can scratch the surface of the panel and cause permanent damage and affect how well the solar panel works. There are commercial cleaning solutions to use or you can use a pool skimmer with a very soft cloth on it.
Solar Energy Technology by Prof. V.V. Satyamurty, Department of Mechanical Engineering, IIT Kharagpur. For more details on NPTEL visit http://nptel.iitm.ac.in.
Don't think the biggest solar panel is the best. There are a lot of variables to consider when buying solar panels. You should consider each of these factors when making your decision.
To gain more from solar panels for a business or home, get installations that have technologies that don't directly rely on our sun's schedule. New solar energy systems can store a great deal of energy so that you can make complete use of your system 24/7, 365 days a year. This is especially useful if you use most of your power at night.