Hey Ben. Here is an idea to consider: Take a class on Italki and record it with some free recording software from the web, (and the teacher's permission) then listen to it over and over again until your next class. Listen to it while driving, exercizing, walking the dog, etc. The teacher will repeat the word you didn't know, and give you the English translation so you essentially have a ready made vocab study list. The places you come up short in conversation with the native speaker are the places you want to concentrate. there are thousands of words being used in any language. the only way to truely get that number down to something manageable, is to converse regularly and see where you fall short. Good luck!