How can I speed up recovery during marathon training?

I'm training for the Marine Corps Marathon in October. This is my first marathon. I'm following Hal Higdon's Novice Marathon training program. This program has me running Tues, Wed, Thurs with increasing mileage. Before this, I wouldn't run more than two consecutive days. I find Thursday's run to be harder because I've run on Tuesday and Wednesday. What can I do to make Thursday's run easier? I assume with time I'll just get into condition but is there a way to help my body adapt faster? Maybe change my diet during those three days?

Any advice would be appreciated.