Without getting into to many specifics I would recommend to add some hill running into your training. I like the water factor and I have used it many times before when I trained both myself and clients. Core is very important and working your upper body should be one of your goals as well. Don’t concentrate only in your legs. Also stair climbing is another tactic I like to use with the clients who are runners because of the multiple benefits you can gain form this type of conditioning. Another thing to keep in mind is to avoid treadmill as much as you can. When you are doing your mileage, do it outdoors. Running in as many different surfaces as possible will improve the conditioning and strength of your lower body. Also it’s great for the mind. There are many other factors and more specifics I can get into for answering your question, but I think keep it simple is the best way to go about it.