To be honest, looking in a dictionary is one of the WORST ways of approaching phrasal verbs. A simple translation into Portuguese will not help you understand how phrasal verbs fit into sentences or explain what context it's appropriate to use them in. Try not to use dictionaries - they really aren't very helpful.
Nor is there any trick, I'm afraid. Unlike Latin-based words which can be broken down into roots, there is no use trying to work out what 'up' or 'in' actually means when used as part of a phrasal verb.
The only way you can really get a thorough understanding of phrasal verbs is the way that we native speakers do - by exposure to colloquial language in natural contexts. You need to read informal texts, watch TV, watch movies, listen to music and try to get a feel for exactly how these expressions fit into our daily lives.