It will not be hard to pay attention to Matt Flynn. He will play the entire first half under center for the Seahawks, and get scrutinized more than any other player on the field. Educated fans will look a little deeper.
Tempo is important. Flynn should be getting the team in and out of the huddle quickly and to the line with more than 10 seconds (preferably 15) on the clock. His pace after the snap matters as well. He should not look rushed or frantic going through his reads or facing a pass rush.
As far as delivering the ball, focus on timing, accuracy and finding the open man. It is harder to see the play develop on TV, but those in the stands should have a good view of where the opening in the defense was and whether Flynn found the person. Timing is best judged by whether the ball is on a player at the time of a break. Accuracy should speak for itself. Look for whether a receiver has to adjust his speed or route to pull in the pass.
Difficulty of throws matters as well. How many throws are short dump-offs or screen passes versus passes that must travel between, or over, defenders? Flynn likes to throw the deep ball along the sideline. Look for at least one deep ball along the left sideline.
Almost as important as the items above is which defenders are in. The Titans likely will not play their first string the whole first half. Look for a few numbers of Titans defensive lineman, and make note when they stop coming in the game. Pre-season games can be hard to judge due to this issue. They are all wearing the same uniform, but you are seeing guys who will start in the NFL versus guys who will never make a final roster in some cases. Russell Wilson will enjoy a major advantage in facing inferior competition in the second half, and he should shred them.
Flynn has shown a propensity for leading scoring drives during camp. It will be important to see how he performs in the red zone, and how he performs on third down. Those two factors are keys to Seahawks season.