Read more:
how to say good night in japanese in true way
Is there only way to good evening in japanese
Pass JLPT N4 listening test after 3 month !

Guide for the best way to learn Japanese, 5 Japanese study tips for Japanese learners and beginners.
1. Learn Japanese like a kid
Let's recall the time when you were still a child, or look at the children who learn to speak. At that time, did your parents explain clearly the exact grammar structure of a sentence, or tell you that "cat" is a noun and provide you a bunch of new words for you to learn by heart? No! That is not a natural way when we learn a new language.
Language can be considered as a habit. Kids learn language by repeating, remembering and using the sentences in appropriate situations. You do not have to focus on grammar, all you have to do is "imitating", learning like a child.
* Personal opinion: In reality, 2-year-old kid can be able to speak and understand plenty of things. As an adult, learning with the kid's method combines with the regular "learning by heart" method may be much more effective than expected. The main point is that: listen and speak the daily life sentences which are regularly used by Japanese people in the most natural way possible, the sentences which are too academic may not be used much. People always say that just forget the boring grammar if you want to have good communication.
2. Try to speak no matter how bad it is
Have you ever seen a kid who speak non-stop about everything he/she saw? For example "that car's color is blue" or "the woman ahead has a so big head", ...etc.... Kid just speak like that and parents do not bother. That is how kids practice language. They use all the time and words they know to describe the life around them. It is a normal thing when a kid say a silly thing, similar to beginners speak the wrong grammar. Do not afraid to speak because the more you speak the better you become.
* Personal opinion: It sounds like tip 1 at first, but the recommendation from this tip is that: use all the opportunities you have to practice Japanese. Do not afraid of wrong speaking or slow speaking. If you are in the academic environment, the teachers will fix for you. In the daily life, the local people will give you some tips, or watch and imitate how they speak in similar situation.
3. If there is a chance, stay at the local people's house (homestay)
Homestay is a splendid way, it is not only the chance learning language but also a good opporturnity to learn more about culture, behavior and the differences between what you have read about Japan and what you actually see in Japan.
* Personal opinion: It is always a good chance to study Japanese in Japan itself, the only problem is economic capability.
4. Read everything on sight
Speaking or regular using of Japanese is necessary, however, reading is also an another important skill which you have to notice. The scariest part for people who study Japanese probably is Kanji. With Kanji, there is no alternative way other than study hard each word. And to remember for a long time, you will have to use every chance you have to read the sentences on sight. They can be instructions on made-in-Japan products, the store signs, or slogan you find on the internet, ...etc...
* Personal Opinion: Normally people tend to learn by heart when it comes to Kanji. However, there is another way to learn Kanji which is by creating sentences or passages related to the Kanji word. This method makes it more interesting and easier to learn kanji.
In addition, reading books, stories (depends on Japanese skill) can also provide vocabularies and natural way of talking and writing of Japanese people.
5. Rewrite many times
Reading mainly help you to remember the old words and it does not help much in remembering the new words. Therefore, you should write down the words you want to learn many times. A Kanji word is very hard to remember so you should also learn it with vocabularies to make it easier to figure out.
* Personal opinion: it is recommended to learn a Kanji word through a sentence. This helps in both remembering the words and also the grammars, in addition it forms the habit of using suitable sentences in different cases. If possible, you can make a dialogue with about 4 to 5 sentences, when you encounter a similar situation, you will feel more natural and easier to speak.