I used the KanjiDamage method, which is similar to Heisig but available online: http://www.kanjidamage.com/. The advantage is that the mnemonics also help you remember the on-yomi for each character. It's not for everyone, though: the author has a filthy sense of humour! Personally, I found that made the mnemonics even more effective.
I've found that mnemonics really only help at the very beginning of learning. But once you even get to 100 things you need remember, a completely unrelated extra thing you have to remember on top of what you actually need to learn becomes too much.
For kanji, just remember the radical readings, and memorize vocabulary with the different readings of the kanji you're trying to learn. Knowing that 貢献 sort of kind of sounds like cocaine does nothing to help me remember that it means contribution. But knowing 献血 and 献金 help me memorize that けん is a reading of 献
I think my failure was more due to me using Anki, then abandoning it rather than anything else. It's a really good system. I tried Heisig for a bit, but KanjiDamage worked a lot better for me. Perhaps if I'd have combined it with something like the goldlist method it would have worked better for me.
