And thanks to my teachers here, I can always know which parts I need to improve. And thanks to my teachers here, I always know which parts I need to improve.

-You don't need 'can' in this sentence -If you want to be more clear about what 'here' means, you can say "And thanks to my teachers on this site" or "And thanks to my teachers in the town where I live"

And thanks to my teachers here, I (can) always know which parts I need to improve. And thanks to my teachers here, I (can) always know which parts I need to improve.

It’s more natural without “can.”

Then every week I find some time to review thoseeir corrections and feedback. Then every week I find some time to review their corrections and feedback.

“Those” sounds odd because you haven’t mentioned any corrections or feedback before this.