Lack of traditional art skills shouldn't really hinder you in something like Bryce. Once you have the basics of how the program works, what you need is imagination and a good eye. Both of these improve with practice, and reinforce each other. Your imagination provides you with a story, one 'frame' of which will become your image. Your eye comes into it as you look at the world around you and notice how things are made, how they fit together, how they look with other things. Then, when your work is in progress, your eye should tell you how the different elements of your image look together - are they out of scale, does the arrangement of objects lead the viewer's eye through the picture? etc. Looking closely at everything is the main skill for any artist, and it starts your imagination running.