Attic Ventilation Gable Soffit, Ridge, Powered,Solar Oh My!! Need Suggestions

Looking for suggestions on attic ventilation. To help save on energy bills. I live in northern Alabama. House is 2350 sq. Standard Ranch style house. (No tall ceilings etc) Not sure if it matters but I will try to explain the foot print of the house. The original part of the house was rectangle with gable vents on the 2 sides of the house and soffit vents every 6 feet or so. Now the house has an add-on to make it an L shape which consists of a 2 1/2 car garage and maybe 10'x20' or 25' family room. There is one more gable vent on the side of the add-on (above the garage) same soffit vents and one whirly vent in the roof.