you never ever seem to use any kind of reference, and until you do a lot of your work is going to be flawed.
thats one of the closest to what i imagine your lighting conditions are...
balloons: shiny, smooth, no-dither!!, lots of AA, bright colors, hardly any shadow,
i'd say that right now, the green character and red balloon don't match, maybe pick a pallette and use it for both to get a unified character/item set.