I just made a successful rainbow rice cake found here.
I used dry rice (no glutenous) flour for this, which is more challenging than with wet flour kind.
The key is to prepare dough early also need more water obviously. As long as you don't feel too much water and it can break when held firmly, it should be ok.
Prepared dough should be kept in refrigerator for overnight. I even kept it for a few days in freezer section and thawed it later this time.
Then dough is more adapted to be used for rice cake. Once you start making it, then just follow maanghi's recipe. I find coarse sift works better for me to avoid dryness in the cake. If it is too wet, you can add more flour as you make.
Maangchi's recipe here: http://www.maangchi.com/recipe/mujigae-ddeok