It is assumed that you will follow best practices and be specific and set out a detailed, clear brief when requesting at least three quotes.
Ask friends and family for a recommendation and check the TrustMark website to ensure that the tradesmen are registered for the particular trades you require.
Use a business that advertises using a landline phone number and be very wary of those only willing to give you a mobile number.
Seek references, speak to previous customers and if a reasonable sized job, visit previous jobs.
Don't just go with the cheapest. Consider your ability to communicate with the business and the quality of their work.
Only pay for work that has been done and not by advance payments. If materials need to be bought in advance by the tradesmen, it is reasonable that the customer is asked to pay a fair percentage of these costs as the job progresses.
Always use a written contract, as it offers you protection if anything does go wrong.
Agree in writing on any changes to the agreed contract value and ensure these are completed before the work is done.