Synonyms for Refine (same or very similar meaning)
WordNet sense 1 (reduce to a fine, unmixed, or pure state; separate from extraneous matter or cleanse from impurities):
rectify
WordNet sense 2 (improve or perfect by pruning or polishing):
down, fine-tune, polish, polish
WordNet sense 3 (make more complex, intricate, or richer):
complicate, elaborate, rarify, elaborate
From the ODE community, based on WordNet
add/edit