what is a good way to learn mandarin?

Hi,

I've tried duolingo for about 2 months straight and all I know how to say is rice, american, italian, english, water and some other useless stuff, it doesn't even teach you to write or anything like that. It sucks.

I know the best way to learn a language is to go to a teacher or something, but I prefer not to do that and learn it online.

It will probably be harder for me since my native language is not english and I doubt there's lessons or something online for mandarin in my native language, but I'm willing to try, I know english pretty well.