When you speak Japanese, what are your hands doing? In the last couple of weeks, I’ve noticed that when foreigners speak Japanese, many of them seem to have a wicked case of what I’ve termed “charades hands.” We all wave our hands like Stan the used boat salesman from Monkey Island:

I’m tempted to say that ESL folks aren’t plagued by “Stan hands.” For whatever reason, Japanese just draws it out of us. There’s so much more I’m trying to express! Can’t you understand what my hands are trying to say! I’ll freely admit that my hands are as guilty as everyone else’s, but I’ve been trying to be better about it recently.
Do whatever it takes to keep them under control. Put them in your pockets. Sit on them. Hold something really heavy. I have a feeling that maintaining control of your hands will force you to make your word choices more accurate and your grammar more precise.
I think mastery of the passive tense probably cuts down on “charades hands” by about 50%, so go ahead and start there.