Regular sewing machine maintenance is a must if you want to keep your machine running trouble free for years.  This means cleaning the machine and oiling it after most major projects.  The machine manual will show you which points should be oiled. 

Computerized machines need different treatment than the standard mechanical machines.  Using the canned air sold to clean dust and lint from computers is an excellent way to clean lint from both computerized and mechanical sewing machines.

A piece of clean, folded muslin can be used to wipe back and forth between pressure disks.  Fold a small piece in half, hold an end with each hand, and work it with a sawing motion between those hard to reach disks.

Some sewing experts recommend throwing away your needle after each major sewing project and using a fresh one for the next project.  The reasoning behind this is that the needle can become dull or bent as you sew.  Bent needles can damage your machine and should always be changed; however, I use my old needles regularly and do not seem to have a problem with them becoming dull.  Dull needles can be run through the little strawberry that dangles from many traditional tomato-shaped pin cushions.  That little strawberry is actually an emery to sharpen your needles.