Begin your journey
So, you may be wondering "where on earth do I begin?", and to that I always tell people this: before you do anything you should first learn Kana. But what is "Kana" anyways?
kana/ˈkɑːnə/ noun
The system of syllabic writing used for Japanese, having two forms, hiragana and katakana. [Source Oxford dictionary - Google]
Japan has 3 (three) syllabaries, or "alphabets" if that's easier for you; these are Hiragana, Katakana, and Kanji.
Hold up! did I hear that right? THREE alphabets?! Yup... why is that? well you see, back in an age where Japan had literally no writing system in place, they may have kinda stolen China's alphabet (Kanji) and implemented it into their own society! Back then the world was a dark and scary place, women weren't allowed to use Kanji to express themselves (yikes), thus Hiragana was born! Hiragana basically were broken dumbed down versions of Kanji, that eventually melded it's way together into written language alongside Kanji, and that's what all Japanese people use on a day-to-day basis now!
Wait... so Kanji, and Hiragana, what about Katakana?
Okay, so Katakana was created as an alphabet to be used when writing "borrowed words", these are essentially words that have been imported to Japan from elsewhere in the world, since Japan previously had no word for that specific thing! E.g.: スターバックス [Suta-bakkusu] Starbucks!
Tip for learning your Kana!
Let's get you started on your Hiragana and Katakana then eh?
An effective way for you to learn these fast and efficiently, is to get yourself a notepad or a few sheets of paper, and repeatedly write down the characters as you say them aloud (I recommend doing a line at a time Eg.: あいうえお is one line, then かきくけこ and so on); repeat this a few times, then try to cover up the ones you've written down and attempt to write them from memory (once again, whilst speaking them aloud).
Once you've got to a point whereby you can write them without looking back at your practice lines, you can move on to the next batch!
Hiragana 「ひらがな」
Here is an example of a Hiragana chart you may find online!
As you can see, each line follows the same sound pattern:
You start with A I U E O and then after that, it simply adds a sound to the beginning, the only exception here is N
Below is a video to help you learn how to write and remember your Hiragana!
Source: JapanesePod101
Katakana「カタカナ」
Here is an example of a Hiragana chart you may find online!
It's worth noting that you needn't stress over learning any new sounds, because get this! they're exactly the same! they're only written a different way!
You may even find some similarities in a couple of the characters to the ones in Hiragana!
Below you'll find another video to help you learn Katakana!
Source: JapanesePod101