Here are the sentences with mistakes underlined and corrected:

1) I often watch **tv** at **my free time**.
Correction: I often watch **TV** in **my free time**.

2) He surfs **internet** every day.
Correction: He surfs the **internet** every day.

3) He **like** listening to music.
Correction: He **likes** listening to music.

4) I **goes** swim every weekend.
Correction: I **go** swimming every weekend.

5) I like reading books. (No mistakes)

6) He **go** fishing every weekend.
Correction: He **goes** fishing every weekend.