Phrasal verbs aren't actually that hard to learn. As they are used in conversational English, you'll learn them by speaking with native English speakers or others who are fluent in English. Reading a lot of English also helps, but you might want to choose blogs or tabloids, as they are usually written in conversational style. I also love listening to the audio drama's and typical programs on BBC 4xtra.
Also, look at the particle. The particles are usually stressed and they determine the meaning of the phrasal verb.
For example: If someone's speaks really quietly, you want them to speak louder. So you would ask them "to speak up", the particle being stressed. Without the particle, or with a different one, the meaning changes or it won't mean anything at all.
Another great tool to learn phrasal verbs is the Oxford Advanced Learners Dictionary. I see they also have an app, but I'm not sure if it's as good as the book.