Marie-Helene Morrow, owner of Puerto Rico’s Reinhold ­Jewelers, offers tips for maintaining mutually beneficial vendor-retailer relationships.1. If I’m doing business, I have to click with the person to click with the jewelry. When I look into the cases, I see the people, not the pieces. It won’t work if I don’t have synergy with the people I’m buying from.2. I wouldn’t ask of a David Yurman what I would ask of a Sarah Graham. I work differently with every vendor, because every person is different. I can’t apply the same expectations across-the-board.3. Give brands time. It can take years before a line starts to sell, and that’s okay. I have faith in them and faith in myself when it comes to [deciding] what’s good and what’s bad.4. There are no perfect people. I’m not perfect. I had a vendor who sold to a different retailer. Businesswise, that bothered me. But as a