Are you wanting to take better photos or create better images? If it is the former, which is an admirable and challenging endeavor, you need time, patience, a good eye for light - and ultimately some expensive light equipment when you realize you don't have the first two.
If you want to create better images, us an editing app like photoshop. Pshop can make up for a myriad of lighting problems. You can shoot in HDR (High Dynamic Range = records more levels of light) or you can achieve it in Pshop.
Whichever, start by shooting from lower in your photo)
A little bit of amateur exposure manipulation in P-shop.