Ok don't crucify me just yet, Mnemonics work for some people, in my experience for most people. They work for me, and thats not debatable. What if, instead of flash card pictures you added some simple but interesting sentences with each character to memorize it? Using the Mnemonic system with wrote memorization would be gold.
I refer you to this book:
http://www.nanzan-u.ac.jp/SHUBUNKEN/publications/miscPublications/pdf/RH/RH%20Simplified-sample.pdf
This is the first 60 pages, I would skip down to the fist visual which is a small flash card with their method on it.