I know the number one issue many people have when learning a language is where to start doing it? I know that was one of my issues.
It does seem overwhelming because of how much there is to learn. But before you start, you have to make the proper preparations.
If you're gonna start learning Japanese, I recommend the AJATT method to start off and get rid of all your native language materials. I like the saying "You won't learn Japanese reading an English manga." And it's true.
If you want to be fluent, you have to really consider the life changes that entails. If you don't want to be fluent, but conversational, that's okay. I still recommend immersion because you'll become conversational that much faster.
Here is what you should do to get started.
1) Find tons of Japanese immersion material. There's music, movies and other things that I guarantee you can find and enjoy. Load up your iPhone with it because you'll want to be listening whenever you can. Graded Readers like this one here can improve you immensely. They're made for those learning Japanese as a second language. They're children's books with audio. Great for vocabulary pick up. No English.
2) Find a course that fits you. Just one. I only recommend starting with one because it can be overwhelming using too many courses at once. I also recommend starting with the FLR Method, but Teach Yourself and Assimil are among other viable alternatives.
3) Find a good phrasebook. Lonely Planet is known to have good phrasebooks. I've used them for various languages. However, I also recommend The Ultimate Japanese Phrasebook. I like this one in particular because it comes with Audio for each phrase. Yes, there is English in it, they say the phrase in English, then Japanese. However, it's a minor issue and something Audacity can easily fix.
4) Get Anki or an SRS. You'll need this. When you learn new keywords or want to get premade study decks, Anki will be your best friend. It'll keep new material fresh for you and it'll make the learning process much simpler. Look at the helpful links if you're not sure how to use Anki.
That's it! It's really that simple. Don't try searching online for easy, quick and painless ways to start learning because you won't find anything worth while. Any time you spend searching, use it for studying and immersing.
It'll be tough not visiting your usual websites and switching to Japanese ones. You'll get annoyed, frustrated and even want to give up. But you'll pull through because it's just a language and millions before you have done it. There's no reason you can't too!
When browsing the internet, install RikaiChan (Firefox) or RikaiKun (Chrome). The dictionary is better than Google Translate and you'll learn a lot of vocabulary. And especially a lot of vocabulary to add to your Anki deck.
So for now, this is the best advice I can give. If you have any other suggestions or comments I'd like to hear them.
では、行くぜ