To me the first volume of the classical Heisig’s work:

James W. Heisig, Remembering the Kanji 1, University of Hawaii Press, 2011, 6th edition.

is the bible of the kanji learning. Replacing rote memorization with clever mneumonics, together with grouping kanjis by the constituting radicals changes the whole learning experience. In my opinion, this is the best system to follow. There are free pdf copies lurking on the internet. You can get one, but of course it will rob you of the experience of owning, reading, and dog-earing the actual physical copy. Something I would not want to miss.