Grammar

Basic Japanese grammar is quite simple. Nouns have no gender, and the distinction between singular and plural is rarely made. Verbs and ajdectives are conjugated simply, almost without exceptions. Nouns are always used in the same form.
The basic word order in a sentence is subject-object-verb, in other words the verb goes at the end.
The subject or object of a sentence need not be mentioned if it is obvious from context. In addition, it is commonly felt, particularly in spoken Japanese, that the shorter a sentence is, the better. Because of this grammatical freedom and the tendency towards short sentences, Japanese speakers tend to omit words from sentences, rather than refer to them with pronouns. A single verb can be a complete sentence: Yatta! "[I / we / they / etc] did [it]!". Or, a single adjective can be a complete sentence: Urayamashii! "[I'm] jealous [of it]!".

Pronunciation

The sound system is relatively simple and limited, so basic pronunciation is easy. As can be seen from the writing systems, the language breaks down into syllables combining consonant+vowel, and if words - even the longest ones - are tackled syllable by syllable, panic and inaccuracy are easily avoided.

Levels of speech (politeness)

The thing which foreign speakers of Japanese find difficult - and sometimes never master - is the use of different grammar and vocabulary used in different levels of speech or politeness: the words and expressions used when talking to a close friend, or a child, are quite different from those used when addressing a customer or a superior.

Titles

Japanese often use the title or surname + title of the person referred to, where pronouns would be used in English. For example, when speaking to one's teacher, the title sensei (teacher) would be used (either by itself when addressing the person, or with their name, Tanaka-sensei). It would not be appropriate to use "anata" (you). Anata is used to refer to people of equal or lower status, and one's teacher has higher status.

The most frequently used titles are:
san: (eg. Suzuki-san)
This is the most neutral and general title, and can be used in most situations.
DON'T use it for yourself (eg. I am Smith-san) or with Mr. (eg. Mr.Suzuki-san). Mister OR san is enough.
sama: (eg. Suzuki-sama)
This is a more polite form, usually used in formal situations and letters, but too polite in a casual context.
kun: (eg. Saito-kun)
This is an informal title used for boys and men who are younger than yourself.
chan: (eg. Toda-chan)
This is an informal title used for young children and close friends (particularly girls).
sensei: (eg. Sato-sensei)
This is a title used for teachers, and by extension doctors and other qualified people, particularly when they are giving instruction or advice.