Use "mir" if there is dative case and "mich" if there is accusative.
As I can see, Albanian language has nearly the same cases as German, thus the situation is not hopeless.
When to use which one, typically there are significant differences between the languages, but not essential. In your case, the problem is that both "mir" and "mich" translates to "mua", i.e. "mich" and "mir" is the same word on your first language.
Also your English knowledge doesn't help you, because it is "me" is the same in both cases.
However, your first language differs in the accusative and dative cases of the masculine third person singular: "atë" would translate to "ihn", and "atij" would translate to "ihm".
Thus, if you don't have a better option, then use "mir" if you would use "atij", talking about a male third person, instead from yourself.
Applying this rule, you only need to learn the differences between Albanian and German, which is already much easier. Exactly where are these differences? No one can list them you, except an Albanian German language teacher (or a German Albanian language teacher, first is much more unlikely).
How big mistake is if you miss: imagine a foreigner using "atij" instead "atë". So it sounds for the native speakers if you use "mich" instead "mir".