I enjoyed learning today, totally immersed in my studyies, and reviewed the contents effectively. I enjoyed learning today, totally immersed in my studies, and reviewed the content effectively.

I enjoyed learning today,: I was totally immersed in my studyies and reviewed the contents (?) effectively. I enjoyed learning today: I was totally immersed in my studies and reviewed the content (?) effectively.

“Content” sounds odd here. What sort of content, or the content of what?

I enjoyed learning today, I was totally immersed in my study and reviewed the contents effectively. I enjoyed learning today, I was totally immersed in my study and reviewed the contents effectively.

It seemeds that keeping your phone away from you is a good way to concentrate! It seems that keeping your phone away from you is a good way to concentrate!

It seemeds that keeping your phone away from yourself is a good way to concentrate! It seems that keeping your phone away from yourself is a good way to concentrate!

It seemeds that keeping your phone away from you is a good way to concentrate! It seems that keeping your phone away from you is a good way to concentrate!

"seemed that" implies that your opinion has changed somehow because it's in past tense. Assuming you still hold this opinion, present tense is better.

When the last class ended and I walked to my dorm, I heard someone singing near the lake, and the song iwas the OST of one of my favorite soap operas!!!!!!!!! When the last class ended and I walked to my dorm, I heard someone singing near the lake, and the song was the OST of one of my favorite soap operas!!!!!!!!!

When the last class ended and I walked to my dorm, I heard someone singing near the lake, and the song iwas the OST of one of my favorite soap operas!!!!!!!!! When the last class ended and I walked to my dorm, I heard someone singing near the lake, and the song was the OST of one of my favorite soap operas!!!!!!!!!

To me, “OST” means “on-screen text.” This didn’t make sense in this context, so after a google search I realized you probably meant “original soundtrack.” Is OST a common abbreviation in your circles?

When the last class ended and I walked to my dorm, I heard someone singing near the lake, and the song is from the OST of one of my favorite soap operas!!!!!!!!! When the last class ended and I walked to my dorm, I heard someone singing near the lake, and the song is from the OST of one of my favorite soap operas!!!!!!!!!

the "OST" is the entire soundtrack, so a song is "from the OST" (as in one song in the OST) rather than being the entire OST.

My sleeping quality is wellhas been good recently. My sleep quality has been good recently.

My sleeping quality isI’ve been sleeping well recently. I’ve been sleeping well recently.

My sleeping quality is wellgood recently. My sleeping quality is good recently.