A solar powered fan for your attic is a good choice if switching completely to solar power is not feasible. The fan will have a temperature sensitive gauge and switch itself on when necessary. This will remove heat and lower the cost of cooling. It's also solar powered, so you don't have to pay to power it.
Before installing solar panels on your roof, check with your home owners association. Some associations have restrictions on what you are allowed to do to the outside of the property, and this might mean solar panels are not an option for you. It is better to have this information up front than to purchase the panels and be forced to remove them at a later time.
Talk to your local government about doing any major solar installations in your home or business. You want to be properly permitted and within building, zoning and construction codes and regulations. However, you may also discover tax credits, rebates and other financial incentives. They may also have data and information about how well certain solar technologies work in your area.