What's the most effective an fast way to cure ringworm? apple cider vinegar? tea tree oil? garlic?

Real antifungal: Tolaftate is available without a prescription. Terbinafine topical is also good. I'd prefer to see you use a topical agent rather than taking medication systemically whenever possible. These should be effective but it may take a few weeks. Apple cider vinegar, tea tree oil, and garlic are promoted on "natural healing" sites for everything -- trying them would be your business. Best wishes.