You can try googling phrasal verbs and idioms. You can also Google slang words but it's probably best to stay away from these words until you have a better understanding of the language. I make flash cards for my students so it's fun an easy for them to learn. hope this answer helps.

If you get drunk, you may get a hangover, later. (not interchangeable) "work out" - can mean exercise, both as a noun and a verb Reni has given the suggestions I'd give. There are dictionaries of slang. Probably web sites of the same. Watch "Friends"? Ask your chat mates to use lots of informal terms.