There are numerous Driving Schools all with different offers all looking for your Business,

and YES  I am one of them.

Below I list what I consider to be the Major factors in choosing  the person who is going to teach you a skill that will stay with you for the rest of your life.

 The Ability to teach you to drive safely ,not just to pass your Driving Test.

• Make sure you have a good relationship with your Instructor(if you dont then your lessons will suffer).If you do not know them, ask to meet them prior to booking lessons with them ,as most will be willing to visit and discuss things .
• Some Driving Schools including National ones use Trainee Driving Instructors,this is legal ,it just means they havent taken/passed there final exam .Trainees have a pink triangle licence, fully qualified Driving Instructors have a Green octagonal Badge ,Ask to see there Badge ,if its Pink you may want to find another instructor or ask for a lesson price reduction as they are using you to practice for there final exam .
• If you are paying for a 1 hour lesson you should have a 1 hour lesson not 45 minutes as sometimes seems to happen.
• Apart from the First hour of an initial 2 hour  lesson for someone who has never driven ,make sure you spend a good percentage of your time driving,Not sitting at the side of the road looking at a manual of how to do the manouvere.(You are spending your money to learn to drive not look at pictures ).
• Driving Instructors should never shout  or make you feel useless, if they do I suggest you find another Instructor. 
• Also some Driving Schools ask you to sign up for a certain number of lessons ,the highest i have heard is 35!!!!!!!!,ask the question what happens if im ready in 15 lessons ,Remember we all have different skills and abilities some may take 40 ,some i have trained have passed in 20 lessons.

                 Thank you for taking the time to read this and i hope you found it helpful.

      Good Luck whoever you learn to drive with and enjoy it.