Translation:How do we improve our Chinese proficiency?
Sorry, but you don't "improve a level"! It sounds very strange to me in English. You can "raise a level", you can "advance your level" or "advance (with)in your level". Also, you cannot "improve your proficiency"! You're either "proficient" or you are "not proficient".
But you can "improve your skills" or simply "improve your Chinese"!
"Improve your level" doesn't sound wrong to me but I agree "improve your proficiency sounds wrong" though not because proficiency is binary either yes or no, after all "more proficient" doesn't sound wrong.
Now I hit this one a few days later and this time I agree "improve your level" does sound wrong (-:
@johnsark: My mind connects "advance your level" to meaningless metrics like Duolingo's XPs, lines of code, and man-months.
Without the 样 it reads more like "why should we improve our Chinese proficiency? " you need the set phrase 怎么样，which means "by what means?" in this type of sentence. (in a different type of sentence it means "what do you think ? Or "how's that?). Sometimes 怎么 (without the 样）means why, but a different type of why than 为什么。you can kind of think of the difference as a how/why compared to a what/why.