It's helpful to clean the ignition leads and coil exterior carefully with a damp cloth at each tune-up, especially if there is ever salt on your roads.

Also dump in a can of fuel injector cleaner twice a year or more often.

Get your OBD codes read (see the FAQ or pay for it) and maybe get the CO level checked by a mechanic.

There are load of other things not by any means unique to Volvos;

- Check the battery water level, clean the battery top, and check the cable clamps for tightness]

- Check all drive belts for tightness and condition

- Power steering and brake fluid levels

- Check the voltage regulator for correct voltage

- etc

- etc

- etc

After all, a Volvo is (mostly) pretty much like any other car and needs the same sorts of things most other cars need.

It's all in the details.