I'm learning with the help of a Udemy course called "El método", Duolingo and Spanishdict.
I started just recently so I don't know if I'm on the best path or even a decent one, but I feel like I'm making daily progress.
My problem with Duolingo is that I need more explanations of the grammar than it provides, but the Udemy course has me covered there.
What I find to be an interesting experience is using my second language (English) to learn a third one, as in my native language there are no good resources available.