What are some tips and tricks to ensure client pays a freelancer after receiving the work?

There is no tip and tricks to it. It’s simple if the client is happy and satisfied with your work he will pay you no dought about this. I have worked with more than 100 clients till date 99.8% of those client has paid (Some are always exceptions) those 0.2% are those clients who either changed there mind about launching the product they were building or were dependent of some private VC to pay them and that VC backend off.

You should follow the approach what we do. It's very important to make yourself & client safe.

1. Divide the project into 3 to 6 milestones have a clear scope of every milestone what you will complete and how the client can check.
2. Take first milestone payment as advance (Sign a contract)
3. After every milestone gets payments, Provide a window of 5–10 days to clear the bill else pause the work.
4. Never provide code or documentation before payments of the milestone, Only provide the code till the milestone work is done and the bill is clear.
5. Never deploy on client-server before final payment, Even if you deploy on client-server don’t share documentation & keys before final payment.

If you will take care of these points you are sorted, But just remember, deliver good work client will pay you blindly, Because the client believes you are an expert and he deserves good work.