The best line-ups will have the two boats fairly close together—to ensure you’re sailing in the same breeze—and the leeward boat either bow-even or slightly bow-forward. If you’re the leeward boat, be sure you allow the windward boat to sail normally. If you get too far forward, or too close, he’ll eventually fall into you and neither of you will learn very much. After 5 to 7 minutes of sailing, tack, switching windward-leeward positions, and repeat. I guarantee trends will be noticed.