Well for alot of newer Euro diesels
Drive it gently untill the engine is up to temperature. They wear out quickly if drivin hard when cold.
Replace the fuel filter when its called for in the manual, diesel is a filthy fuel.
Oil changes with synthetic oil and other services at proper interval
If its an Auto have the fluid changed by about 80-90k miles
2001 Audi S4 2.7T
2000 Audi A8L 4.2
1998 Audi A4 quattro 1.8T
1999 VW Beetle 2.0