How do I stop my colored pencil drawings from looking flat and muddy?

The muddiness usually comes from overblending or layering too many colors without letting each layer breathe - try limiting yourself to 3-4 complementary colors per area and use light pressure on early layers so you can build depth gradually. Also, leave some paper showing through (especially in highlights) and save your darkest values for final accents; that contrast and negative space is what makes colored pencil work pop instead of looking dense and lifeless.

I've found that a lot of the flatness comes from not enough value contrast - people focus on color so much they forget to push the darks darker and keep the lights really light. One thing that genuinely helped me was switching to a white or light cream pencil as a final pass over highlights instead of just leaving the paper showing through; it sounds counterintuitive but it actually makes those areas pop and gives dimension. Also work on your layering order: lay down your lightest, brightest hues first, then build darker and more muted tones on top, which is the opposite of what some folks do. That way you're not fighting the paper and you get actual depth instead of that cloudy, stuck-together look.