How can I tell if my inside geraniums need water or have too much water? Sun exposure?

I need some help figuring out if my geraniums are watered too little or too much. The symptoms seem to be the same: wilted leaves, yellow leaves that turn brown and die. By the time I re-water or dry them out, it’s too late. Am I missing some symptoms? I’m really tired of losing them! Also, what is the best sun direction for these plants to receive during the winter at an inside location to make them grow full and “close to the soil” instead of long and leggy?