As of today, I have owned 3 automotive detailing businesses since the age of 17. I am now 42, have worked with business partners and have also incorporated some of the above ideas into the last couple of shops I owned.
I did enter into the corporate world for a number of years and retired last year not wanting to deal with the stress or politics ........... and really wanting to do something for myself once more. So here I am ..... auto detailing with my third shop. Definitely a passion for me.
I'll throw in a couple of ideas that have also worked for me that I would suspect would be good for just about any detail business ........
1.) Check with a reputable body shop regarding clean up of customer's vehicles. This isn't going to pertain to the exterior of the car as much as it will the interior of the car. Body shops simply don't have the time to devote to properly cleaning the interior & will usually blow it out & vacuum along with cleaning the windows. There is always going to be body shop dust that was missed. I offered interior services (sometimes custom polishing to the exterior) to body shops who had customers they wanted to "keep happy" or had extenuating circumstances. With this idea you are providing a service to the shop as well as to a customer who will likely spread the word.
2.) Combine services or share space with another automotive type of business. In my case, I had shared space with an automotive upholstery shop. This shop mainly did custom & replacement OEM interior, convertible tops and vinyl work. Many times a customer would want each of our services. Splitting the cost of leased space is always a good idea & the added advertising potential is invaluable.
3.) Fleet services are a bread & butter income for the times when you may become slower. If you have a mobile unit & are able to secure a contract or two with a large fleet (UPS, FedEx, Roadway ... trucking companies are good for weekend work) then you could hire a couple of people to help wash the vehicles on the weekend. I pay help $10 per hour and will average 8 -10 hours per day working during a weekend. Weekends are great for this work as the trucks are typically not being used, are parked with easy access and will fetch the higher price of say $9 per wash. No windows and no drying required. Past crews I have hired would average 75 - 130 trucks per weekend.
Just some ideas for thought ............ .02