Here's the process for the springs:

Front
Remove the 2 14mm nuts on the strut towers.
Jack the car up
Remove the wheel
Remove the 14mm bolt at the top of the strut fork
Remove the 2 12mm bolts that hold the brake lines onto the strut assembly (you may not have these, my '95 does)
Remove the 17mm nut and bolt that runs through the bottom of the fork through the lower control arm

Let the fork drop down and slide the strut assembly out of the fork and pull it down from the car (leave the fork there)

Once one is out, use a spring compressor to hold the spring down so it doesn't shoot out and kill you. Once you have the spring compressed, use an allen wrench to hold the top of the strut rod from turning and take the 12mm nut off. Slide the cap off and then uncompress the spring.

Install the new spring and try to keep the spring ends in the grooves on both the bottom cup and the cap. You shouldn't have to compress the new springs if you're installing lowered springs. Reinstall the cap and tighten the nut.

Install
Slide the top of the strut assembly into the 2 holes in the strut tower.
Place the fork back onto the strut assembly and make sure you have the tab on the assembly slide into the opening on the fork. There is a little dimple on the bottom of the strut assembly that needs to go on the same side as the bolt so it will slide in correctly.
Tighten the upper fork bolt.
Make sure that the 2 upper bolts are in the tower holes and reinstall the bolt through the lower control arm and the fork.
Reinstall the 2 12mm bolts for you brake lines (if you have them)

Before you start driving the car again, make sure that you've remembered to put the 2 14mm nuts back onto the bolts sticking through the strut tower.

Repeat for other side