I have never tried blogging to learn a language; that's a very interesting approach! I have used Duolingo, Anki, and www.FreakyFastFluency.com, all with decent success. I will have to try out the blogging approach though, I am always up for new ways to study:)
I use a combination several resources: www.FreakyFastFluency.com Anki Flashcards Duolingo They each have their upsides and downsides. I like to combine the use of all of them to try and pick the best aspects of each resource. Hope this helps!