Mexican Gastronomy

Mexico is one of the countries with the most delicious food, well I think so ;)

The typical food here in Mexico are Tacos and only here they exist. I have heard others people of others countries that say "The Tacos taste not well" but Let me say you that lamentably you can taste the true Tacos only here in Mexico because anywhere in the world prepared them as here.

If you have the opportunity to visit Mexico, you have to eat them.

Corrections: 

well I think so - Should be: well, at least I think so.

I have heard others people of others countries... -

First we'll start with this part of the sentence: I have heard others people... The word 'people' is a plural noun that requires a singular adjective to come before it. Likewise, the word 'others' is also a plural noun when used by itself. For example: "The others followed Tom into the taco shop." In the example sentence, the word 'others' is used to describe a group of people. When you put the words 'others' and 'people' together side by side, they do not form a gramatically correct sentence because they are both plural. In your context, you used 'others' as an adjective. When 'others' is used without the corresponding noun (people) it becomes a noun rather than an adjective. Therefore, WITH the corresponding noun, 'others' changes to 'other' with no "s" on the end (others => other). The same goes for the next part of your sentence: 

...of others countries... - Apply the same rules from earlier to this chunk of the sentence and the corrected result will be I have heard other people of other countries...

"The tacos taste not well" 
- This part should be "The tacos do not taste good." First of all, good try! The negatives in English are not easy to master but I know you can do it with practice. Instead of using well in your sentence, you should use 'good.' Here's a reference on this rule: http://www.elearnenglishlanguage.com/blog/english-mistakes/good-vs-well/ 

Let me say you - You forgot to put in the word 'to' into this sentence. It should be: Let me say to you. This is something called an infinitive, which are also seen in Spanish. In English, infinitives are seperate words. Reference here: https://www.youtube.com/watch?v=z8A2sEefW0s 

lamentably - Stop using Google translator ;) I caught you! The word you're looking for to fit here is 'fortunuately' (o afortunadamente en español).

The complete corrected paragraph:

Mexico is one of the countries with the most delicious food, well at least I think so. ;)

The typical food here in Mexico are tacos and it is only here that they exist. I have heard other people of other countries that say, "The tacos do not taste good," but let me say to you that fortunately you can taste the true tacos only here in Mexico because nowhere else in the world prepares them as they are prepared here.

If you have the opportunity to visit Mexico, you have to eat them.