There really isn't a run that I don't start off by saying to myself I'm going to maintain absolutely nothing faster than, say, an 8:30/mile pace (pace depends on distance, obviously). And there really isn't a run that'll I'll be a half mile into when I'll peek at my Garmin and see that I've actually taken off at a spritely 7:50/mile pace.
Then I'll overcompensate and run at something like a 9:10/mile pace to get myself back to the 8:30 pace, but when I finally get to that average pace a couple miles later I'll have been running so slowly that I'll feel too strong and too good. So my pace will slowly but surely creep back down to 8:20 or 8:15/mile and then BOOM I hit 7 or 8 miles, crash and find myself shuffling to the end of my run and finishing with an 8:50/mile -- or worse -- average pace. Something like that happening never seems to fail. Or always seems to succeed, depending on point of view.
This isn't me, but it could be me at the end of any of my longer runs.
After four years of running you'd think I'd have a grasp on how to handle my longest runs, but the truth is I have a theoretical grasp only. I've never been able to take a run plan in my head and put it into effect out on the road. Ever.
I hate trolling for comments, but most of the advice I find on a topic such as this come from elite/pro runners who have all of their runs micromanaged to the most finite detail for them (for the most part... the "self-coached" runners generally just think more mileage solves all problems), so I ask you, the internet: What strategies do you use to start and maintain and nice even pace over the course of an entire long run?
P.S. For trolling for comments I'm sure my punishment will be to have no one comment. That's ok because it's what I get.