Here I will summarize a couple of things that have worked for me when it comes to language learning. And I hope they can help you to!
1. Discipline!
Set a time in your busy or not so busy schedule to study. It can be 30 min or 1 hour. Anything you feel comfortable with and!!! unless there is something crazy going on make it a daily task!!
Why do I say daily? It is very easy to fall in the trap of: "I'll skip it today, I'll do it tomorrow", then that tomorrow might become a month or even never again! So even if it's just a few minutes, don't skip it!
I also try to divide my days into the different things that are needed to learn a language:
Grammar
Reading
Listening
Writing
Speaking
2. Grammar!
For the grammar I use a the "Matome Doriru" series. They have these series in all JLPT levels and it has multiple choice questions that include Kanji and grammar rules. They also have translations and explanations. So very useful.
However! I don't write on the book itself. I like to keep clean because that way I can always go back to it and do the questions all over again fro extra practice.
What I do instead is having a dedicated notebook where I write every single question. Of course, this means it takes me longer to finish the book and I'm only doing one page a day, but it helps me so much in terms of practicing writing new kanji.
There is also a saying in Spanish "The one writes, studies twice" meaning that it is easier to remember information when you are actually writing it down.
The other thing I really like to do is color coding!
For the most part, I like to write using pencil, just because I tend to make mistakes writing kanji and I don't want to scratch things out or make my notebook messy. But specific notes I like to use red pen and black pen. Red pen to extra highlight things and black pen for meanings and translations.
I also like to use my dictionary app Imiwa? to verify certain meanings and not only rely on what the books is saying.
3. Reading!
For reading I use the The preparatory course for JLPT book. For these series I particularly like the "Reading" book. It doesn't have any translations, which makes it a bit dull to use. However, it also forces me to translate things myself.
So I like to read paragraphs in this book and write one like a time in my notebook. then leave space for furigana, meaning of words and the translations of the sentences.
Then, whenever there's a topic that I'm not truly familiar with, I look for more information online and get myself a bit more familiar with the culture.
4. Listening!
I've been falling in love with NHK easy news. The reason why I love this website is because I can listen to the podcast first and then look at the manuscript for anything that I wasn't able to understand.
The other reason is because I become familiar with words that are the current "hot" topic of the moment. For example I've recently learned a lot of new words about "Corona Virus"
Then what do I do with the new vocabulary? I make posts about it. I like creating posts for my instagram account where I share the new vocabulary but not only that it is also so much quicker for me to just open my account when I want to remember a specific word rather than my notebook... that's probably because I keep my phone with me at all times. So that has become very useful for me lately.
5. Writing!
I started using iTalki to improve my writing skills when I started learning German and it has become one of the best tools I have ever used.
iTalki has a section called "notebook" where you can write your own paragraphs or sentences and native speakers correct your entries. This is a free tool and a very handy one.
After I get the corrections I have my own diary where I write the corrected paragraph with all the suggestions.
6. Speaking!
I will get into more details about speaking on another post. But what I like to do is to have video chats with friends or participate in Japanese societies here in my city.
One of the things that I've been wanting to do is to get a private teacher, mainly because my friends don't really correct my mistakes, but it has still helped me a lot to improve my communication and think faster in the other language.
