When do use 'Mich' and 'Mir'?
This is seriously confusing me help!
Mir is the dative and Mich is the accusative. Although there are some exceptions. You also use the dative (mir) with the following prepositions: aus, außer, bei, mit, nach, seit, von, zu, an ... vorbei, bis zu, gegenuber. You use the accusative (mich) with the following prepositions: bis, durch, für, gegen, ohne, um, entlang.
There are also prepositions, that require Dativ or Akkusativ, depending on the questions you can for the acting verb.
Wo? (where?) => Dativ
Ich befinde mich im (=in dem) Wald. = I am in the forest.
Wohin? (where to?) => Akkusativ
Ich gehe in den Wald. = I walk into the forest.
Those prepositions are: an, auf, hinter, neben, vor, über, unter, in, zwischen
"entlang" is a bit tricky. Using it as a PREposition it requires Genitiv or Dativ.
Ich ging entlang des Weges / entlang dem Weg = I walked along the way.
Using it as a POSTposition (or adverb) it requires Akkusativ.
Ich ging den Weg entlang. = I walked along the way.
There is a general rule of thumb for using accusative and dative cases. This is one of the most difficult things for English speakers because this distinction is not drawn there. So what is this distinction?
Accusative case is used when an entity is used or applied or just subject to an action or state. Ich sehe ihn.
Dative case is used when an action applied or state has an (internal?/constitutive?) effect on an entity (such as enrichment, delectation, deprivation, ...). Ich schenke ihr ein Buch.
This is a general rule of thumb and it will hold in most cases, but there are loads of exceptions.
for me, of me, to me, ...: mir
(pay attention to exceptions)