You'll need to:
* Consult a repair manual: A factory service manual for your specific year, make, and model truck will be the most accurate source.
* Inspect the truck yourself: Carefully examine all suspension components, joints, and other moving parts that might require lubrication. Look for Zerk fittings (the little nipple-like fittings where you apply grease).
Expect a significant number, likely in the dozens, not just a few. Be prepared to spend some time checking everything thoroughly.