Here is a handy guide that will prepare you for any kind of plumbing disaster at home.
1) Know how to turn off the water supply
Find the main water supply switch/tap and turn it off before you begin any kind of plumbing work
2) Get the metal connectors in their right place
If two different types of metals are joined, then one or both the metals are bound to corrode.
3) Make a list of things you dismantle
Not every faucet or shower head is the same! Take pictures at each step when you are dismantling a fixture. This way you can put it back in the right place.
4) Don’t over tighten the fittings
Over-tightening can strip threads. Hand tight is good, let it not be cranking.
Top Tip: If you wish to join two pieces of dissimilar metals, you will need a dielectric union. It insulates those two types of metals and prevents corrosion.