1.  Take a course in Jr. College Auto Mechanics.  You will find it
profitable because with even one course under your belt, you will be able
to do many minor jobs and definitely all routine maintenance work yourself.
My experience is 80% of your knowledge is gained in the first course and
20% in subsequent courses combined.

2. Power Steering fluid should be changed at least every two years.  It
gets dark from oxidation and the molecules "shear" destroying some of the
properties.  I don't know about particles, but the pump will wear out
eventually no matter what you do.  Its made lousy.  Symptoms of wear out is
lumpiness while smartly turning steering wheel with car stationary.  The
pump cannot keep up with the fluid demands UNDER PRESSURE.

3. Follow the manual for plugs.  Often substitutions are tolerable because
each manufacturer's stock numbers overlap and approximate the others.  Its
not that critical.  If a spark plug "misses" you will feel it "buck" a
little especially during heavy load and acceleration.  If there is no
missing, all plugs are the same in that the will ignite the mixture.  There
is no plug which will enhance power; only plugs which diminish power
through missing.  You will learn a lot about plugs in Auto Shop I, but the
most elemental fact to keep in mind is "heat range" and this is determined
by stock number.  Other factors are diminsional, materials, resistance, and
the like, but for the most part determine whether or not the plug will even
fit in the hole, how long it will last and how much radio noise it will
make.  Study up.

These days, 99% of a tune up is just replacing the plugs.  Long gone are
the skilled adjustments I love to make by tinkering with the systems.