In my opinion, the best way to study and memorize phrasal verbs (and any other words) is to study them in context (in a full sentence) because otherwise you will get confused easily.

Maybe you can write up mock dialogues between two people to practice them in context? For instance, with the phrasal verb "to calm down", you could write: Mark: How ate my lunch? Mike: What's wrong? Mark: I made lunch last night for work and some idiot ate the damn thing on me! Mike: Okay, well try to calm down. I am sure there is an explanation for it. Mark: Explanation?!? I don't see any reason that someone should be eating something that they didn't cook, even if it was left in the fridge without a label on it saying "DO NOT EAT"!!!! Mike: Yikes. You could also try to use the word in as many grammar patterns as you can. For instance, 1. He never calms down. 2. After she calmed down, we went to the movies. 3, After she had calmed down, we went to the movies. 4. Will you please calm down? 5. I can't calm down right now. I am so pissed off! 6. I don't know what to do because he isn't calming down. 7. I don't want to calm down right now. 8. Tell him he has to calm down or the neighbors are going to hear him yelling and will call the cops. 9. She scolded the boy who would not calm down. 10. Calming down right now is the least of my concerns!

I agree with Georg - you need context (full sentences) to understand them. This is because the meaning of a phrasal verb can change depending on the object, subject, other prepositions or even other elements in the sentence. Definitely avoid looking for definitions in a dictionary. That will only confuse you. There's a lot of misunderstanding about phrasal verbs, even by teachers, in spite of them being so common in English. You can start practising phrasal verbs at the website below, but please remember the definition that is given only is correct for the example sentence. http://www.roadtogrammar.com/phrasalverbs

I think you just have to memorize them. The thing with phrasal verbs is that they don't really have a reason... we say something a certain way just because. The best way is to just memorize them together so you never forget.