Start with the application
Nail down the connector family (MC4, SAE, XT and so on), current rating, target market, order quantity and packaging before you compare anyone. The clearer this is, the fewer quotation rounds you go through.
Check where the MOQ starts
On a first order you rarely want a full container. Ask where the MOQ starts and how fast samples move. Ours start at 100 pcs, with samples in about 7 days.
Ask about customization early
If you run your own brand, ask up front whether logo, color, packaging and material can change, and at what quantity. Photos, drawings or a physical sample cut the back-and-forth in half.