When I'm using Skritter, I feel I'm missing out on audio and pronunciation reinforcement.
An easy software change may be to play the audio for the character ever time a stroke is drawn within a character, or every [x] seconds.
I'm thinking that the "stroke action generating the audio" would further reinforce the mental relationship between the character and the (audio) word.
Even more difficult and further departure from your core product, would be to have more audio. Perhaps one or two sentences of audio showing how the Chinese word is used in a sentence, just to hear Chinese speech and get the ear accustomed to the sounds. Printing the Chinese sentence with the spoken audio in this case would even be better. Sorry, this suggestion is a further departure from your current product.
Perhaps you can do this with the synthesized TTS system by just reading sentences from a book? (if your program already does this, then I haven't got far enough into it yet.)