I know what I want to do and I know what I have to do to do it. [And I know how to write a confusing sentence.] Getting there is the tough part.
I love the little details of planning for a race far in the future, but each time I think I'm ready to start actually running - because the only workout that matters is the one you actually do - I find that there's yet another stage of preparation I'd overlooked.
Right now, the days that will be the easy days are the hard ones. I'm trying to build my mileage (from zero), but I know that just running slowly will become a problem eventually, so I have to add days of short fast stuff. "Sometimes you have to run one hard and fast," some clever guy once wrote. One day per week of 40-50m sprints will help keep me from ossifying. One day of form-work strides will help make those sprints improve over time.
What I want to do for a long run is just way too long at present and I have to be patient, so my training right now looks like it's good for a 10K (and I have a 10K race scheduled in October!):
Monday 45 minutes with 4-6x100m strides @ 1500m pace
Tuesday 90 minutes
Wednesday 45 minutes with 4-6 all-out sprints of 40-50m
Thursday 90 minutes
Saturday 90 minutes
Sunday 120 minutes
That's a lot of unusually long runs for a 10K schedule, but I really need to work on my endurance. When that becomes easy to do, it's on to the next stage, which I of course, have all planned out. I just have to remember that this is preparation for a longer race next year and not turn it into a hard schedule for a 10K which I'll race so hard I'll spend the winter recovering.