2004 325i Power Steering Pump

Need guidance on changing my power steering pump, shorten the learning curve

Make sure you buy the correct one - LF20 vs. LF30
Order a new reservoir and hoses.
Consider ordering an aluminum PS pulley to replace the factory plastic one.
Consider changing your water pump pulley at the same time (aluminum).
"Rent" the fan clutch wrench at Pep Boys (if an automatic trans)
Get at least 2 quarts of auto trans fluid (Castrol Multi Import meets the Dexron/Mercon specs
Get 2 new belts (might as well swap them at the same time).
Plan on flushing the fluid a couple of times once changed until it's cherry red (that's why you need the extra quart of trans fluid).
Get a new o-ring for the high pressure hose to pump.
You can remove the reservoir to cooling coil hose from the cooling coil by pushing forward and using an open end wrench to retract the plastic coupling. Otherwise, buy the tool for $35.
Loosen the PS pump pulley hold down bolts before removing the belt.
Be prepared to clean lots of stinky PS/trans fluid.
Make sure you have metric sockets and Allen key sockets and Torx (internal and external) sockets.

There are a bunch of DIYs showing how to do this - it's not hard, but it is involved.