Where's the money?
How could you do something so vicious? It was easy my dear, you forget I spent two years as a building contractor — Vincent Lugwig's response to Jayne in the hit film The Naked Gun highlights what is a challenging industry to operate within.

Produce a clear itemised quote which clearly explains the work you will be undertaking. Detail what you have included as part of the quote, and perhaps more important what isn't. List any assumptions which may not be evident during an initial site visit. If you are quoting from a set of plans, make sure you include the reference numbers and dates in your quote.
- The client will remove all furniture and carpets before we start work.
- We can complete the work in a single site visit.
For a small project will you expect payment on completion? If so, it might be a good idea to invest in a low-cost payment terminal so that you can take a card payment on completion.
A bad example
-40% on completion of the second fix wiring.
-10% once installation is tested and commissioned.
We reserve the right to invoice on a pro-rata basis if the project is delayed for reasons beyond our immediate control.
Unfortunately, sometimes you will have no option but to take things further and take court action. You must be able to show that you have tried to settle the claim before taking court action - if you can't you may be penalised by the court.