Proper habits to stay motivated?

Goal: “catch up my grammar to the N4 level”

System: “Read a chapter from a Japanese grammar text book (or equivalent from a site such as Tae Kim) every day.”

System: “Watch a Cure Dolly grammar video every day.”

System: “Read/watch native material every day, and look up unknown grammar as it comes up.” (I often recommend the Absolute Beginner Book Club for this, especially if you’re mid-N4.)

Note that none of these systems are specific to N4 grammar. Instead, they’re for grammar in general. Some of these will help you learn all N4 grammar, but you’re also picking up N3 and higher grammar along the way.

Goal: “becoming conversational in the language”

For this, systems would minimally include a daily schedule for learning new grammar and new vocabulary (very important to be able to speak!)

You might also include a system of daily shadowing, but that might be better saved for when you know more grammar and vocabulary.

There’s a section here on the forums for writing in Japanese which can be useful to participate in, such as a system of posting something in every thread that comes up. (I’m not familiar with that section, so I don’t know the details on how it works.)

Whether having such a variety of things to do will impact your motivation, I don’t know. But getting into the habits for daily activities that will slowly improve your knowledge in various areas will also increase your capabilities. As your capabilities increase, you can do more (read more quickly; write more complex sentences), and that may result in a motivation boost.

That said, always remember that motivation is not your friend.