What's the difference between "Eu não gosto daquilo" versus "Eu não gosto desse?" Both mean "I don't like that."
A better alternative would be "Eu não gosto disso". The difference then is simply a matter of the location of the thing you don't like in either space or time (far: "aquilo"; nearer: "isso"; but both translated as that). Using "desse" means you know about the thing in question (the word tells us it is masculine) and in context you would read it as "that (car)", "that (plate)" or whatever.
There is a good overview of the differences between words like "isto/isso/aquilo" and "este/esse/aquele" here: https://www.duolingo.com/comment/3857621
Eu não gosto daquilo= I do not like that.
Eu não gosto desse I do not like this one.
The problem is that the verb "gostar" (like) requires the preposition "de" (of). To say "I do not like that" you must say the Portuguese equivalent of "I not like of that" (no "do"). Translating this word-by-word gives "Eu não gosto de aquilo" but "de aquilo" (of that) must be written in the contracted form "daquilo" giving the final version "Eu não gosto daquilo".
i finally understand the difference between "daquilo" and "desse", but what about "daquele"? thanks!
"Daquele" is similar to "desse", but when you use "daquele" (related to a masculine thing), the object is farther then if you were using "desse";
"disso" refers to a present thing, as you were pointing at something. "Daquilo" is used when you want to refer to a past thing, like something you ate yesterday.
In this example, we could have you daquila also ? How to know if we should use the femine or masculine form ?
"Daquela" (not daquila) is used with a feminine noun. "Daquilo" is neutral and works and it makes no reference to a gender.