Could you correct me, please? I´m training for my english exam!

Pop Music Festival in Madrid

Last week, I went to a Pop Music Festival, and I´m going to tell you about this it.

As I see it, I believe that In my opinion, the best parts in of the festival were was when the dancers did a spectacular and amazing performance with fluorescent paint. They switched off the lights, and we only saw saw only the bright paint. It was awesome!
Another important moment was when “XXX” appeared. It was incredible and excited!. so exciting!
All the people who where were in the performance sang her songs with her.

And the other hand, I think that The worst part was when we wanted to eat, because we were hungry!. There weren´t any places to eat at all. nothing!.
If you didn´t take your food, you had a seriusly problem! were out of luck!

In my opinion, As I see it, the bands and singers that played there, they were perfects!. perfect. Their performances liked I liked their performances very much. Moreover, the lights effects were gorgeous!.!
The audience enjoyed it a lot, include including me!.. I was eager here!
If you can go the next year, I recommend you it!

It sounds like the festival was lots of fun! Your writing is very good.  One error that you made consistently was using double punctuation.  You should use a period or an exclamation point, never ever both.