Writing to practice my English. Could you correct me, please!

Your next travelling to XXX

I´m going to tell you about the charm of XXX.

XXX is an spectacular, amazing, appealing...city. It has a lot of things to visit. For this reason, it´s very difficult to choose someone. ( any is used only in negative sentences or questions) 

I love XXX. Therefore, I´m eager to write about it. In XXX there are many places with a big history and many modern places too. You choose it! 
 I like very much to go for a walk to a park in the centre of the city called XXX. There is a very big pond with goldfish. Moreover, you can sail in a boat. 
You can find little monuments as well...and all around you is green. If you like the trees, you must go there, because there are many kinds of them.

Also, XXX has got Al´s cathedral. It´s amazing! This cathedral is a place where our prince “F” was married. It is a big history in XXX. 

And If you want to enjoy, you should go to Theme Park. I know you have got another in your city, but this is different! There are a lot of restaurants and very funny attractions!

I wish you could enjoy it!

Writing to practise my English. Could you correct me, please!

You're next travelling to XXX next.

Remember what I said about verbs with '-ing'. They become adjectives or nouns. 

Ex:

The rain that is falling = The falling rain  ('falling' is an adjective)

The boat which is sinking = The sinking boat  ('sinking' is an adjective)

The process of washing clothes = The washing ('washing' is a noun)

None of these examples were full sentences, you'd use something like 'the falling rain' or 'the washing' as an object or subject. A full sentence is:

I'm travelling.

You're doing the washing.

The boat is sinking.

The rain is falling.

"You're next travelling to..." isn't technically wrong, but it's a very odd sentence. Putting 'next' after 'travelling' could work, but 'next to' means something else. Here it would mean you're sitting next to XXX while travelling (ie. XXX is a person). If XXX is a city, it's best to put 'next' at the end.

I´m going to tell you about the charm of XXX. 

XXX is a spectacular, amazing, appealing...city. It has a lot of places to visit. For this reason, it´s very difficult to choose any one.
Nothing is wrong with 'thing', but 'place' is better.

I removed 'one' for the same reason.

You seem reluctant to call XXX a city haha

I love XXX. Therefore, I´m eager to write about it. In XXX, there are many places with a lot of history, and there are many modern places too. You choose it!
I like very much to go for walks to a park in the centre of the city, called XXX. There, there is a very big pond with goldfish. Moreover, you can sail in a boat.
You can find little monuments as well...and everything around you is green. If you like the trees, you must go there, because there are many kinds of them.

If you're saying want you want to do in the future, say "I'd like very much...". If you're saying you like walking in general, say 'walks'.

"All around you is green." It's not wrong to use 'all' as a noun, but it's a little awkard here.

Also, XXX has got Al´s Cathedral. It´s amazing! In this cathedral is where our prince “F” married. It is a bit history in XXX.

Saint Al? Why not?

And if you want to enjoy, you should go to a theme park. I know you have got another in your city, but this is different! There are a lot of restaurants and very funny attractions!

In a city with Al Cathedral and Prince F, I'm not surprised there's a theme park called Theme Park!

I wish you could enjoy it!