Planning to keep my car for 10 years, where do I start?

I usually change cars every few years, but with everything costing more now, I've decided to keep my current car for the long haul, maybe 8 to 10 years. This is totally new for me and I want to make sure I'm doing everything right to avoid major problems down the road. I found a detailed article about annual check-ups that really focuses on long-term car reliability tips. It explained how regular inspections of things like the cooling system, suspension, and electrical components aren't just about fixing what's broken, but about preventing future wear and tear. It also stressed the importance of keeping service records. For those of you with high-mileage cars, what are the most important things you've done to keep your vehicle running smoothly over many years?