First off, good vid, thanks for posting. I like your game, and I think you can improve a lot in the near future. As far as tips/advice, my thoughts are as follows.
In general:
-Improve your positioning. When you've hit a defensive or floating shot against a guy who's hitting aggressively, you should retreat to give yourself a better chance to run down the next ball. This needs to happen as soon as you hit the ball. When you hit an aggressive shot, then move up tighter to, or even inside, the baseline and be ready to take the next ball early.
-Your defensive movement is too lateral. When Matt hits a good groundstroke deep and toward one of the sidelines, you tend to just run straight across the baseline to try to get there. You need to move back as you move in the direction of the shot, on an angle, to intercept the ball deeper. This will be a little more intuitive if you're following the "improve your positioning" part.
Conversely, when he hits more of an angled ball, you want to move forward as you move across to cut it off before it gets lower and wider.
Watch the very first point Federer plays in this clip to see both of the above illustrated:
https://www.youtube.com/watch?v=OwpT8ZXJk3Y
Notice that after he hits the return, he recognizes that he's hit a defensive shot and he's playing against a guy who's looking to attack, so he immediately starts giving ground as he prepares to play the point. When Berdych hits the inside out forehand, Federer doesn't have to retreat too much because he's already at a reasonable defensive depth. After hitting another defensive shot, he again retreats because he's anticipating playing more defense. Berdych hits a big crosscourt forehand, and Federer quickly drops back at even more of an angle to put up the lob; if he had gone straight to his right, he probably isn't getting to that ball.
Against a good player like Matt, you're going to have to be able to commit to playing some defense when the situation calls for it, which in your case is going to be after hitting second serves, hitting serve returns, and of course any time the opponent hits a good offensive shot.
-Defensive shot selection. When you're stretched wide, give the ball more air to give yourself time to get back in position. Also easier to get it back deep when you hit that type of ball. If you're only able to hit a defensive ball short, try to keep it low, since a ball below the net is harder to attack.
On your serve:
-Need to get more first serves in. You missed quite a few in this vid. Even if you take something off of some of your first serves to get more in, it's less likely to be attacked than any second serve so long as you keep the guy honest by going after a first serve a reasonable percentage of the time.
-Related to the points in the general section above,
but you need to move/react faster after you serve. Be ready; against a good player like Matt who's attacking a lot of your serves, especially your second serves, you should be dropping back into a defensive position immediately after serving if you feel that the serve you hit is likely to be attacked. This will depend on how the points are going. Conversely, when you hit a good aggressive serve, you should be on your toes, looking to move in a bit and attack the next ball.