I watched your video and I have some pointers. I didn't read /u/Keeeeel's post until after I made comments, so you can compare ours and see where we have similar advice.

• 4:52 – Don’t pass the ball to them. You can tell that both of the opponents are facing the opposite way so you’re alone with the ball. Take the time to move the ball to the left of the field where your opponents are not.
• 4:45 – Right when the opponent hits the ball at this moment, you need to go as fast as you can towards your goal. Like REALLY fast. You got lucky with that save!
• 4:26 – Who’s closer to the ball at this moment? You or your opponent? If your opponent is, then stay defensive rather than challenging the opponent.
• 3:57 – Same question as previous one. Sure, it seems like a 50/50 of either you or your opponent hitting the ball right? However, opponent has a shot on your goal and you don’t. Don’t take that chance unless you’re confident that you can block it.
• 3:51 – There’s not much you can do about this one. It was up to your partner to hit it, but he missed.
• 3:47 – Only one person on your team should go for the kickoff. You need to be able to communicate this with your partner. The person that doesn’t go for the kickoff can hit the ball right away if it doesn’t move from the middle. Or this person can get boost behind them. Or this person can go straight to the goal to defend.
• 3:30 – Bad positioning. Only 1 person on your team should go for the ball. What if the opponent (Chewbaca), hits the ball over you and your partner? The best thing you could have done at 3:30 was to stay near your goal and let your partner hit it (do this only if your partner can hit the ball before your opponent can).
• 2:29 – Not much you could have done here. Your partner should have hit the ball as it bounced off the wall.
• 1:37 – Again, who’s closer to the ball? Don’t turn around and attempt to hit it unless you know you’ll reach the ball first. It’s possible that the opponent could have just hit the ball right over your head and into your goal.
• 1:05 – You or your opponent hitting the ball here first depends on skill level and who has enough boost. If your opponent had enough boost, he could have easily jumped and boosted to it first since he’s closer. However, you going for the ball here should be fine because even if your opponent hits the ball first, you know that your partner is behind you to get the ball or play defensive.
• 0:28 – Pause the video here. Your opponent has at least 3 choices here. I’ll list the common ones. He will (1) Hit the ball on the wall so that it bounces back to his teammate to hit it in. He will (2) Hit the ball so that it rolls on the wall making it fly up so that his teammate can aerial it into the goal. He will (3) Try to shoot the ball on the right side of your goal. The best thing you can do in all 3 situations is to slow down and see where he hits the ball because he will definitely hit the ball before you do. Your mistake here was that you didn’t slow down and you rushed for the ball, causing it to bounce right over you.
• 0:24 – In this situation, driving backwards and still being able to control your car to hit the ball takes a lot of skill. Since this is the case, the best thing you could have done is hold the drift button and turn your car (keep holding drift) until your car is facing the ball.

Let me know if you have any questions. It was fun analyzing the video!