the toughest thing about this biz is not the install side, it is the sales side. you gotta make the maximum dollars in a very short amount of time. too many folks look at what they make in a day and think- "wow, that is way more than I make cutting grass in a day" or just fill in the blank with your other income generating business.
I try to explain to my consulting clients on pricing, to just imagine a mowing season compressed into one month. how would you price mowing then? you would need to recover all your overhead from trucks, trailers, equipment, insurance, and cover all your labor and gas expense, from one month of billing. The pricing would be wildly different. That is basically Christmas lights. you really only get November as a month to generate income.
yes, they are up until you take them down in January, but you can only sell and install in November, with earlier rehang customers possible after you have been in business multiple years.
to answer your question, yes, many books out there offer a nugget of info here and there that will probably pay you back for whatever you paid for the packet. the first or second of these you buy and read will pay you back tenfold. but as you buy more the info is repetitive. But even after doing this for many years, I still stop and talk to the guys that are at shows and pick their brains to see what is new and different. anything that can help us install cleaner, faster, easier, better I am always looking for.
And reading these threads over the last 5 years are probably worth 10's of thousands of dollars in saved mistakes if you take the time to do so. and that, of course, is free.