Get as much volume in as possible, spread out evenly through the week, at a pace that's within about 20 seconds either way of 6:30. Ramp up to that pace during your workout, paying attention to the sensations.
Warm up, followed by miles in - 7:00 - 6:50 - 6:40 - 6:30 - 6:30 - 6:30 - Cool down.
If you can't do that workout 3 days in a row, then back off on the intensity just slightly. The third day your legs should't feel like you have much snap, but you should be able to get through the workout. On the fourth day you rest. Then repeat another 3 day block of 5-7 miles at that pace. As you get to understand yourself better, you can cast away your watch and run by sensations, which is a much more advanced way to train. You want to slowly bring up the mileage you can sustain week in and week out at a level that corresponds closely to your threshold.
By "threshold", I refer to a specific sensation that corresponds to a fairly narrow mode of thought. That is, when right near your threshold you are forced to concentrate on the task at hand, or rather, your mind is drifting very little on anything not associated with running. You may be feel as if you could run at that pace for a very long time, even if the reality is that after an hour at that pace you would be hurting. As you increase the intensity beyond your threshold your mind goes into a form of thinking which tends towards "I'm flying...I feel good...but this pace is not sustainable too long...my legs are starting to burn a bit...etc."
I don't expect this to be of much insight to you now, but I believe you'd be well served to slightly alter your goal while running. Don't go out there so that you can run faster in the future. Get out there to find a pace that silences your mind, or what is more likely, brings your thoughts down to a minimum, such that your brain is not racing from one thing to the next. That is the higher goal of exercise, to bring our minds and our lives a greater level of serenity. It just so happens that the pace that corresponds to the mind tending towards silence also allows for maximal long term volume at training intensities that elicit substantial amounts of aerobic development.
When you are sure of the race you wish to peak at, being racing once a week at a comparable distance, and allow yourself to go all out in those races, but, and I stress, do not cut back your volume whatsoever so that you might be fresher for that race. You taper when you are ready to pop a big result, and in time you will see that only then does a taper really allow you you produce a result that is a cut above the B-level racing you had done leading up to it.