Last Saturday, I was watching the new movie ''Conjuring'' with some friends.

It was the first movie I'd ever watched in an actual cinema so i was a bit excited.

I came by bustook the bus there but my friends told me that I had to be careful because there were people who racketed other people.

As the other commenter said, not sure about racket...

My friends weren't being racketted because there was a vigil (a security man) who said tosecurity guard who told the racketters to stop but they hadwere lucky.

Again not sure about racketting or racketters, just correcting the grammar. Also who was lucky?

Afterward, I arrived inat the cinema and we watched the movie.

We had good laugh with my friends because sometimes, there were screamers.

''At times'' sounds more natural here, but it's not a big problem

I advice you to watch'd recommend you guys this movie if you don't often watch scary movies / I'd recommend you guys *watch* this movie if you don't often watch scary movies.

Advise (verb written with an s) is generally used in slightly more serious/formal contexts

But if you really want to be really scaredwatch a scary movie, I think the two first were better (I didn't watch them but I saw it onin theatre, but I did see them on the internet).

But if you want to be really scared --> But if you really want to watch a scary movie / But if you really want a scarer / But if you really want a scary movie, I think (blah blah) / But if you really want a scary movie to watch ...

I came by bus but my friends told me that I had to be careful because there were people who racketed otherwere pushing people over.

But I know that the verb "racketed" doesn't sit quite well here... I'm not sure what you were trying to explain here.

My friends weren't be racketgetting pushed over because there was a vigil (a security man) who said to th racketterstold them to stop, but they had luck people got their chance to get away.

Afterward, I arrived inat the cinema and we watched the movie.

We had a good laugh with my friends because sometimes, there were screamers.

To avoid unnecessary repetition of "my friends", I replaced it with the pronoun "we".
I don't think the comma is needed in this sentence.

I advice you to watch this movie if you don't oftf you don't watch horror movies often, I recommend watch scarying this movies.

Another way to word this:
"If you haven't watched any horror movies before/yet, ..."

But if you want to be really scared, I think the two first two were better (I didn't watch them but I saw ithem on internet).

Another way to word the first sentence:
"If you want to get a really good spook, ..."