This is a very delicate question, each one studies in a different way, and achieves a different performance and result. In this article we will do a little analysis on what can be studied and how. Remembering that it is my tips and opinions.
To start, abandon the romaji, learn at once hiragana and katakana. If you don't want to quit romaji and don't want to learn hiragana, you shouldn't even start studying Japanese, you will waste your time. A little effort and in 1 week you will be able to learn hiragana and thousands of doors will open, and you will be able to read most of the Japanese texts, and any text you have furigana.
Now let's start to examine a little bit of each thing to be studied in Japanese, and a good suggestion and way to accomplish this. There is no order of what to study first, it all depends on your need and priority, let's talk about that too.
This is the main part of learning Japanese, you must focus on learning words. for that you should focus on reading, listening as much as possible, and learn and memorize correctly. Do not try to forcefully throw new words into your vocabulary, try to naturally learn them, just study content.
Increasing your vocabulary is a great way to start learning Japanese, if you focus on that, you will automatically learn other things like kanji, grammar, etc. But remember, don't push yourself! Focus on the ability to remember and not memorize.
How to increase my vocabulary naturally? Listening to music, using anki, reading and browsing Japanese websites, studying Japanese material, using applications and dictionaries. There are thousands of ways to increase your vocabulary, but don't be in a hurry.
Start by learning the verbs that are the most important, by learning them, you may be able to understand and create sentences without difficulty. But don't forget to learn adjectives, nouns and others simultaneously. Learning the verbs is just a suggestion of priority that you should have.
Be careful, Japanese words have different meanings and uses. Only time and immersion in the language will solve this great difficulty.
The great enemy of learning Japanese, sometimes worse than kanji itself. Japanese grammar is very easy, but it is completely different from our Portuguese, and it has thousands of things that we don't know. Verbs are conjugated differently, the order of words in a sentence, the use of the particle and more.
For this reason, avoid using automatic translation tools, as they will always be wrong when it comes to grammar or using the correct word. The first step to do is to learn in detail the particles, and the conjugation of the verbs. Then focus on absorbing content, reading texts, listening to phrases. The more phrases you hear, the more phrases you'll be able to create without making mistakes in grammar.
If you have difficulty with any part of Japanese grammar, such as particles, verbs, focus on it. You have to focus on your weaknesses. Weak points will only get weaker, and will always slow you down. Do not forget to delve deeply into the details and differences that the language will present during the entire journey.
Japanese ideograms take forever to learn. Many are terrified of them, but don't be afraid. Kanji are necessary in Japanese reading and writing.
If you want to learn Japanese quickly, and you don't want to become any artist shodo, then leave the learning of writing in the background. Learning to write kanji for kanji will only delay your learning by years, and will not help you memorize them. After I stopped trying to learn kanji for kanji, without realizing it I learned thousands just by reading and studying.
Take a text with furigana and start reading. When learning words, be sure to learn them with kanji, especially verbs. Verbs use a large number of kanji and are easier to memorize.
Learning whole words is more beneficial than learning to read each kanji, because what is the use of learning to read if when you read the word, you read wrong? Therefore, the correct way to learn kanji is not to worry so much about them, but about reading and absorbing content.
One thing you should learn and study in detail is radicals. Learning the radicals makes it easier to memorize kanji, and even write them.
When studying Japanese, keep in mind that you will make mistakes, you will fail, you will be irritated, you will become discouraged, you will forget ... Remember that this is all part of the learning process.
There is no right order to learn Japanese, there is a right way. There is an order where you prioritize your learning, I do it as follows:
My study priority:
In my opinion, this is the most effective way to learn Japanese. If you follow this priority, you will automatically learn everything else. Is that you? How do you learn Japanese? What is the order and priority of your study method?