Phil Savage is a former NFL scout, was a Player Personnel executive for the Ravens and Eagles, and was the GM of the Browns. He's now the Executive Director of the Senior Bowl, and part of his role there has been to create video media to go along with their website.
He and the Senior Bowl team put together a series of videos that help explain how NFL executives and scouts evaluate players at different positions. They're great learning resources for the run-up to the Draft if you're grinding tape to find players you think might help the Seahawks.
Here, Savage breaks down tape of centers. The players he breaks down aren't particularly important - what I take away from these tutorials is a glimpse into the methods that scouts and personnel executives use when evaluating players.