As explained in the Help Center (see How do I ask a good question?). However, learning a language involves many things, such as:
- learning to pronounce its sounds correctly (mainly the pronunciation of individual words),
- learning to pronounce its typical intonation patterns (at the sentence level),
- learning grammar (not necessarily by learning grammar rules),
- learning vocabulary,
- developing listening skills,
- learning to read its writing system (at least if different from any writing system you already know),
- learning to write in its writing system (in many scripts, handwriting looks different from printed letters),
- developing conversation skills,
- in some languages, e.g. Chinese, learning how to look up words in a dictionary (handwriting recognition is making his easier now),
- learning cultural aspects, since languages never exist in a vacuum,
- finding learning resources (digital or in print, online or offline),
- finding tandem partners, teachers, etcetera.
When you simply ask, "How can I improve in language X?" (or in foreign languages in general) without specifying a clearly delimited area, your question will be too broad. If your question was closed as "too broad", please review the above list of areas to get an idea how you can narrow down your question. You may then find that you can split up the original question into several separate questions.