If you want to learn the Japanese really quickly, you will have to know about the use of formal and informal Japanese language. You will have to know when to use the formal language and when to use informal. A Japanese class focusing on the Japanese language will always lay emphasis on this aspect of the Japanese language.
When you are talking to the different people, you will have to express things in a different way. If you are talking to a Japanese friend, you would want to be expressing your joy in a different manner than what you will be doing while talking to your Japanese boss. This is the main reason why you need to know the difference between the formal and the informal Japanese.
Once you have learnt the difference between these two dialects of Japanese language, you need to move forward. You will have to work on your vocabulary. Remember that building the Japanese vocabulary is not that easy. You will not only have to attend Japanese class for vocabulary but you will also have to put in a lot of effort at the personal level. You will have to read things written in Japanese. You will also find great help from the TV and the films. You will learn many new words which are used in every day conversation. You will also have to find a company where you can stay at your leisure time and speak Japanese. If you can get all this done, you will quickly build Japanese vocabulary.
Also try to watch some Japanese dramas. These dramas are based on real life and they use the real life words and sentences. The other good thing about the dramas is the variety of the characters. This will mean that you will have the opportunity to learn different words. You will also be able to learn what to say in different situations. You will learn the formal communication because the dramas will have characters who are officials and all that.
Hiragana is another thing which can help you to learn Japanese quickly in a Japanese class. You will be able to learn the Hiragana in less than a month. Once you have learnt Hiragana, you will be able to pronounce the Japanese words in a better way. Your accent and pronunciation will be much improved and you will be talking like the native Japanese after some time.
Many people will recommend you to learn Romaji as well. It is believed that in order to learn Japanese quickly, Romaji is a must. But this is not true. Romaji will waste your time and you will not get a lot of benefit from this. So just skip it and move on to learning the Japanese after you have learnt the Hiragana.
With all these things, you are all set to speak like a Japanese native in a few months. If you want to speed up the process, get yourself involved with the Japanese culture as well. It will help you a lot. You will come across Japanese and you will communicate with them. This will help you to learn the things quickly.