lake I live in SC, the weather is average, what maintenance can I do now to make my severely patchy lawn grow.?

Talk to one of the local people that do yardwork as to the best time, but you'll probably need to start by having your yard aerated then let them put down fertilize and gr seed. You should probably put down some straw to keep the moisture in, especially on the bare spots. I'm from SC too and there's some pretty knowledgeable people doing such yardwork. It'll probably cost a couple hundred depending on the size of your yard but it should pay off in the long run. They will usually give you a free estimate.there