If you are unsure of the carpenter's ability to provide service to you, ask them what type of education they had in the field. They should have three to four years of classroom education with apprenticeships or other on the job training with someone. Most will have a formal education in carpentry to provide you with.
If you are planning to build or repair something around your home, every carpenters knows that the first step is always to make a plan. You should have a piece of paper with all of your measurement written down. You should have a clear understanding of how to cut, place and secure each piece of wood. Do not wing it, but give it the time it deserves with a few details.