Discuss how to improve the below terms of payment.

The buyer has to arrange a payment guarantee issued by ... (the name of the buyers bank) for USD (amount) in favour of the seller, covering the buyers payment obligations according to contract. The guarantee shall be advised through ... (the name of the sellers bank) and shall have reached that bank not later than 30 days from date of contract and be valid for 30 days from last delivery as stipulated in the contract.