I'd advise writing out a list of words you want to know, and looking up their kanji (I remember some site called Kantango, which I used during my A-Levels), and using flashcards to help you memorise them.
Also, get a book, or look for a site online where you can learn the grammar.
Now you know the hiragana and katakana, you need to learn how to make sentences. If you can make simple sentences, then practice every day by writing down in the very least 1 sentence about something you did today.
Good luck learning Japanese!
EDIT (of course, you can take this ad infinatum. If you feel like it, and become able to, write a whole journal entry each day.. But, one step at a time, eh?
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