contrast, contrast contrast contrast and shapes! I dont know whats going on looking at this. but here is my interpretation of whats going on. (check paint over) in the block out stage, you want to present your darkest values as soon as possible and that will provide you with more context for comparison for the light. the biggest questions i see is WHAT IS GOING ON? what are you trying to show? if you can answer that with shapes, values or even with a sketch, then you'd be closer to a successful painting.
feedback for you actual question. Interest and dynamism is all in the shapes, do you want sharp rocks to instil a sense of danger? then use sharp shapes for rocks. , even though alot of painting pipelines may show a loose initial block in, it is important to define what you want to show the audience as soon as possible. readability is all about shape design and contrast. so put in your darkest values asap.