See my Writing Japanese article.
If you want to learn how to write in Japanese, bear in mind that it's going to take a lot of time. You may want to reach a reasonable level of fluency before you choose to do that. So unless you are scheduled to arrive in Japan tomorrow, it's more important to focus on those aspects of the language that are more helpful and take less time to master.
If you want to live in Japan, writing Japanese is going to be important. Otherwise, only learn to write if you're passionate about it. These days the ability to produce kanji from memory isn't nearly as important as it used to be. Most people type on their phones or computers, and typing is done phonetically.