Correct errors
"my school is small so everybody knows each other. we have got 200 students and 30 teachers there. the lessons are interesting and the teachers and nice and .
the building is just renovated with a new main entrance,   a computer lab and a school gym. the only place which still needs renovation is the chemistry lab. unfortunately, it isn’t equipped enough.
the corridors in my school are tidy and colourful. so are the classrooms. i like my school because it is a friendly place and i fell safe there."

If you mean grammar and spelling, I’ll help!

“My School is small, so everybody knows each other. We have got 200 students and 30 teachers in my school. The lessons there are interesting, and my teachers are helpful.

The building got renovated with a new main entrance, computer lab and gym. Unfortunately, the chemistry lab lacks equipment and did not get renovated.

The corridors and classrooms in my School are tidy and colourful! I like my School because it is a friendly place where I feel safe.”

Okay! So you were missing a few commas and did not capitalize School. School is a place, and therefore a noun (person place or thing).
I gave one of your sentences an exclamation mark (!) because I felt it fit the sentence! Feel free to change it to a period (.) If you want.

I gave you some new vocabulary just to blow away your teacher! Thank me later :). I made sure to stick to your example though!

Great job! Good luck.