I'ma newbie so don't take my advice as gospel. I would reccomend drinking plenty thruogh the day and then cutting back one to two hours prior to your run. As for stretching do it frequently... FREQUENTLY!
it helps to avoid injury and keep your muscles warm. I injured myself and i was very willy nilly with strecthing. do it before, during and after. Do some lunges at your kitchen sink, while drying dishes, stretch your arms while reading the paper or watching tv, rise up on tiptoes and lower while in queues at the supermarket... who cares what anyone else thinks...
it is only going to do you good.
keep up the good work!