It needs to be clearly stated in the contract that the terms of payment are: delivery by installment and payment by installment.
That is, you hand in a part of the manuscript, the customer accepts it (you can ask for revision), the customer pays you part of the money, then you hand in a part of the manuscript, and he pays the other part.
The wording of specific contract terms can be determined according to whether it is a book or a paper, whether it is divided into several parts according to chapters, or according to the number of pages of the manuscript.
Never pay the full amount after the client accepts all the drafts. My classmate was fooled the first time he worked as a part-time translator. After all the translated manuscripts are sent to the entrusting party, the other party will not give money. Fortunately, my classmates still have the original. If you don't pay, you can't get it back
And installment payment, even if the customer defaults, can only rely on the last part of the account.
Moreover, if the customer is dissatisfied with the quality of your translation after the first part of acceptance, or even refuses to submit the request for revision, the contract can be terminated in time, thus saving the waste of your translation of the full text but not being recognized, and the customer can also find someone else to translate it in time. Good for both sides.