Set the fan speed on high except in very humid weather. When it's humid, set the fan speed on low. You'll get better cooling, and slower air movement through the cooling equipment allows it to remove more moisture from the air, resulting in greater comfort.
Whether you intend to install insulation yourself or hire a contractor, make sure that you know the guaranteed minimum R-value you are looking for. Have any contractor state that installed R-value as part of the bid. Also, prepare for the project by assessing what needs to be done to reduce air infiltration before installation. Include the cost of these added components and labor in your cost calculations. Keep in mind, too, that a tight home requires ventilation, so you may need to take another look at your bathroom and whole house ventilation strategies. Armed with all of this information, select the insulation that meets your energy efficiency, budgetary, and installation requirements. The end result will be a job well done, with energy and cost savings to tally long into the future.