What can I do to prevent delays and ensure a smooth process of the shipment?

Firstly, make sure your supplier overseas (on imports) or if you are the supplier for an export shipment, creates all of the necessary documents correctly (packing lists, commercial invoice, original bill of lading-OB/L) and in a timely fashion, so that all documents are provided with the necessary banks and sent to you (the importer) or your buyer-consignee on the B/L (if you are the exporter) at least 1 week before cargo arrives the destination so that everything can be processed through customs ahead of schedule and freight can be paid along with presentation of the original B/L. One factor that usually slows this process down is when there is discrepencies between the buyer and supplier and since the goods are not paid for, the OB/L has not been surrendered by the Supplier to the Consignee (buyer)