Hello Josh, If you don't mind my jumping in here, I'd first like to say that the show is entertaining. It's not my style, but that's probably because I'm an old geezer.
I believe the answer to your question depends entirely on what kind of cleaning you are doing and what kind of target you have.
When I owned the dry clean delivery business it was "effective" to put flyers on door knobs. Whenever I needed an influx of new customers to meet monthly goals it was easy to send out guys with door hangers and pick up 10-20 new customers in no time. But those were not my top targets. My top targets were entire corporations where, when done properly, I could arrange a presentation at a company meeting and pick up 30 or more new customers in one day. I could pick garments up from ONE designated spot within the building, sometimes doubling or tripling the profit over individual home deliveries.
When Shelly had the DMV business it was "effective" for her to advertise in the yellow pages. She averaged about 20 new customers a month from that. But it was much more effective for her to spend $40 over and over again on cookies, snacks, lunches, etc that she could take to the car dealerships to woo the managers where just one contract with a dealership would mean up to 400 new customers per month!
For me, a home delivery meant more fuel, more time, and even with a higher gross, meant less profit. For her, she gave the dealerships discounted prices up to 50% and STILL made more profit.
In the end we pulled both yellow pages ads and quit marketing to any individual accounts, preferring bulk accounts.
The same thing applies in this industry.
When I started my air filter service it was residential only. My charges were as much as 8 times what I charge for commercial accounts now and I was still barely profitable. Having to deal with hundreds of different personalities, billing accounts and all the fuel costs made the entire process tedious and barely profitable. Flyers, mailers, door hangers, phone calls, yellow page ads, newspaper ads, and all that stuff certainly brought in customers, but it didn't bring in that much cash flow.
Moving on to individual accounts within shopping centers, etc, while discounted more than individual services was my next move. Flyers, radio ads, personal sales calls, and other such methods brought in customers, but the cost to bring in new customers was high.
From there I made a minimum account size goal, paring the target down to customers who had the number of buildings to produce a minimum of 10,000 filters/yr. That narrowed my marketing down to less than 200 targets with a core "premium" target group of less than 50. These respond to lunches, dinner meetings, sports tickets, dinner passes, and personal emails and letters among other things. These take time. I've worked on some as long as 4 years before I got anything from them.
My son, Chris started off taking anything he could get from house washes to driveways to parking garages. Now his target market is similar to mine and he won't even take residential calls at all. His marketing includes many of the methods we use and he has dropped the flyers and other methods that bring in customers he doesn't want.
My nephew does residential only. Flyers, a well marked truck, advertisements, and all the other things that get the attention of residential customers works for him.
The answer to you question varies depending on the target. There is no "top 5 ways to waste your money" that fits all contractors here.
If you want to discover the top five ways to waste your money on commercial concrete cleaning, there are few who have the years of experience that Ron has to answer that question.
If you want to uncover the top five ways to waste money on marketing to government accounts then Phil or Scott Stone are great sources for that.
If you want to find out the top five ways to waste money on marketing coil cleaning and air filter cleaning, I doubt you would find anyone who has made more mistakes and wasted more money than I have.
On the residential end there are numerous guys who can make that list. I'm sure, as long as he has been in business Everett Abrams can tell a new person a lot of ways to waste money on wood marketing.