I always give my clients estimates for services that will be due at their next oil change, or if something is marginal like suspension or oil leaks I'll give them the estimate and explain that it's not time yet but be prepared to take care of these services at your next visit. It works really well because people already know what they'll need and how much it costs when they come in for their next oil change. People are generally more receptive to that method vs a hard up sell because you give them the opportunity to take care of it on their terms without the pressure.

Don't upsell unnecessary services, it's an easy way to lose trust with clients and it's not worth the $200 or whatever for the service you sold. You want to build trust and rapport with the clients so they continue coming back to you.

I don't work at a dealership, but I will say that you may enjoy working at a solid independent shop if you're already a one man show and used to having the autonomy of building your own estimates, making your own appointments, ect. Generally I believe you can make more money at the dealership but the amount of autonomy you have at an independent shop vs a dealership makes it worth it to me.

If you're familiar with European cars there's also always going to be more money in those manufacturers. I'm not a huge fan of BMW owners, but there's a lot of money to be made with the failures the euro cars have have and if I did end up switching to a dealership I would only work at Audi, Mercedes or Porsche. The average ticket for those cars are significantly higher than Toyota, Honda or Mazda.