1. Learn the hiragana. I suggest you do it in groups of give: with a few exceptions, it's always a, i, u, e, o, and something in front of them (and the group with nothing in front of them). You'll need this to be able to learn kanji. Also, the characters for furigana are the same as for hiragana.
2. Learn the katakana. Do the same you did with the hiragana, they're represent literally the same sounds so for each hiragana, there's a katakana and vice versa. You'll need these for foreign words and such, and you'll definitely encounter those. You'll also probably need these to study kanji.
3. Waste your life on the kanji. You'll need both hiragana and katana to do so. Each kanji has one or more meanings, and most kanji characters have several different ways to pronounce them depending on the context. Almost everything that's not written in katakana is written in kanji, and not a whole lot if written in katakana so this is your goal. At the same time, study grammar. It's not that hard but it's different enough from English that you need to study it a bit to get a hang of things.
As for other tips, I recommend you practice handwriting. It's easier to remember what the characters look like if you do so because you need to know each individual stroke which, in my opinion, makes recognizing the characters easier. Do this for all character sets (hiragana, katakana, kanji). There's about 48 of both hiragana and katakana. Then there's thousands of kanji, of which I've read you need at least around 500 to get a hang of things in simple texts. Japanese kids learn around 2000 kanji in school, so that should give you some perspective.
As for myself, I don't have a whole lot of experience with Japanese yet so maybe I'm all wrong. I know the hiragana, the katakana, and around 100 kanji, so there's that. I'm thinking I need to find more time for Japanese though, before I forget...
