What is a one-sentence summary of the following article?
Often the manual for the gun will have specific areas needing oil, but a quick look at where the gun is wearing will give you a good indication of the needs.  Be sure to oil the areas around rotating parts, such as the bolt and trigger assembly. Try to keep oil away from the openings into the firing pin housing (oil is a collector of dirt and powder buildup, and buildup around your firing pin can prevent it from firing). Don't forget to oil the bolt rails and the grooves in which they ride.
Oil all the components requiring lubrication. Reassemble the rifle and make sure all parts are functioning properly. Wipe down the whole gun and remove any excess oil.