More knowledge is nearly always helpful but that might not be the problem here. Many of the best pieces of music don't actually have the best musical ideas contained within them but they work so well because they have a strong sense of structure and dramatic flow. After all, music is a temporal art. The listener wants to be taken on a journey of some sort.
When I'm stuck, I often find it helpful to listen back to what I've written so far and ask myself a few questions from a listener's perspective: Where, as a listener, would I like this piece of music to go next? Should it lead to a climax then fade out? Would the piece benefit from a calmer section? Should the piece explore contrasting material or expand on current material? Should the new material be reached suddenly or do I need a transition? Is there a sense of growth/progress to the piece so far? etc.