So I like to think of myself as somewhat in shape, sure I've gained weight after college but I try to stay as active as possible. I have a friend who had been wanting to run a half marathon but kept backing out because nobody would run with him...so I took it upon myself to help him and challenge myself. Is there anyone out there with any running advice? I've started off slow, we have until December and I've been running about 3 to 3.5 miles daily. Any advice to increase mileage/endurance for these types of runs?