New controls and rewiring
Rewiring or installing more efficient controls can be a very effective investment, with a fast return and 'pure gravy' savings for years afterward. One of the best ways to save on lighting bills is to turn off some or all lights in an area when they're not needed. If your present switches don't give you enough control. You will want to consider rewiring and installing additional switches or dimmers. Your electrician can tell you if rewiring will be simple and inexpensive or more complicated and costly.