I know this drama was on the second series. I know this drama was on the second series.

It is a bit difficult to work out what suggestions I should give concerning verb tense in any one sentence in your whole piece here. However, having read through everything beforehand, I would say that the above sentence could be written as follows: "I knew this drama was on its second series."

Even just tThe first series was got a lot of good reviews, but I didn't like it so much because I felt the jokes were too frank and the characters unreal. So, I stopped watching it. The first series got a lot of good reviews, but I didn't like it so much because I felt the jokes were too frank and the characters unreal. So, I stopped watching it.

I have tried to bring together several of your individual sentences so as to make your text flow better.

But that time when I try to watch it. But that time when I try to watch it.

See above.

I didn’t feel great at all, the jokes are too frank, the characters are not real… I didn’t feel great at all, the jokes are too frank, the characters are not real…

See above.

So, I stop watch. So, I stop watch.

See above.

Now, its theon season 3. Now, its on season 3.

Surprisingly, this time, I canam enjoying watching it. Surprisingly, this time, I am enjoying watching it.

However, if you Just pretending that you are a teenagers again, you will definitely enjoy it more. However, if you Just pretend that you are a teenager again, you will definitely enjoy it more.

Again, I've tried to make your texts flow better.

You will definitely able enjoy more. You will definitely able enjoy more.

See above.

Just don’t tell your parents that is me to suggest watch this drama. Just don’t tell your parents that is me to suggest watch this drama.

Could be written as: "Just don't tell your parents that it was me who suggested that you should watch this drama!" I would put an exclamation mark at the end.