I agree that anyone who installs Christmas lights should have excellent training, and install lights in such a way that looks pleasing and most importantly not endangering the folks that live there.
On selling, marketing and technical merit, I am reminded of selling cars 17 years ago when I was helping a friend that needed salesmen. I studied all the options and specs on all the pontiacs, isuzus and cadillacs, and made it a point to walk the lot every morning and know what used cars we had traded for. I actually thought that being informed and being able to answer questions intelligently would help me sell. But watching the other sales folks, and watching potential buyers buy from other dealers, I learned a seemingly impossible truth.
People buy wrong.
They make decisions that are bad for thier finances and bad for thier family, and do not listen or care to listen to reason when it comes to spending money. And those bad decisions are mostly the result of a very good ( or bad ) salesman who knows how to take control of the customer and close them no matter what.
I had a competitor several years ago who closed 2-300 new customers in 3 years by selling walmart c-9 lights and doing it cheap,cheap cheap. he was a great salesman who went out of business in year 4 because he had no clue how to run a business. he sells real estate now, and probably does quite well, because he is a great salesman.
I think you can succeed in this business by being great at what you do, having an excellent reputation and selling the best product. but if your competitor is a better salesman than you he can and will close work that you would have gotten, even if he does crap work.
I read, train and work every year to be a better salesman and have a better Christmas light biz.