As someone who has been a self employed tradesman for forty years next year, I would recommend that you find someone who....
has been recommended either by a friend/family member or another tradesperson whom you trust.
someone who is fairly local and easily contactable.
someone who comes across as intelligent and respectful.
someone who has a waiting list and cant start tommorow.
someone who is happy to be paid on completion of work, giving money up front is a massive nono.
Interim payments are ok for bigger jobs, but being able to withhold payment if you are not happy is your insurance.
Remember, anyone with any business integrity will have the means to supply materials/hire costs etc before taking payment from clients.
If you are not happy with someone before work commences then dont use them.
There are lots of genuine and skilled tradespeople out there who will take the necessary care and commitment to ensure your work is completed properly.
Hope this helps and good luck.