Please point out my mistakes

I agree with Cheung, lots to improve on. Focus on one or two things at a time. Here are my observations from watching a few minutes of footage;

1hr:45 – You were still moving backwards when hitting an overhead shot. Get under it first, then you can move into the shot (more power, accuracy etc).

Stand AT the T when serving. You have a partner to cover the rest of the court. Standing up to 10cm closer to the net means the shuttle is in the air a shorter time, and should be harder for the opponent to attack.

1:45:59. The way your racquet moved looked unnatural in the smash. I can’t tell the reason, it just doesn’t look natural.

1:46:20. You seemed to jump after you landed on your lunge and kept moving another step to the right. The point of lunges is to rebalance you to be ready for the next shot.

1:46:43 If you do a straight drop, either you or your partner should cover the net returns. Maybe a bit of mis-communication, but one of you should cover it.

1:46:54. Look at the height of the shuttle when you make contact. It looks like it dropped below the net cord and you could have taken it a bit sooner and a bit higher.

Can armchair analyse more if you want. But information overload can be detrimental :)