Tips 1:Do not put Big Order Initially.
Do not purchase the full required quantity in your very first order. Make a small order and figure out whether the quality and other procedures are properly met.
Some suppliers may be putting the MOQ(Minimum Order Quantity) as, say for example, 1 Ton. If you feel that this minimum order quantity itself is large for a sample test, you can contact the seller for still lesser quantity. The sellers will oblige in order to build your trust.
Tips 2: Increase the order quantity GRADUALLY
Even if you are satisfied with your testing orders, do not go for very big orders straightaway. Some sellers may be generous in their first few supply but lock you in the big orders. So, Increase the order quantity GRADUALLY.
Tip 3: Check the Internet
Do Google Search to find out any scam is there related to your Seller
Tip 4 : Gold Suppliers are Not Scam Free.
Do not think that a seller who is certified as Gold Supplier means he is perfect.
When alibaba.com lists a supplier as a gold supplier, basically they check the existance of the company and some other credentials.