Shielding is an important spiritual practice and can be done to protect your energy field from spirits, negative energies and even other people - I don't mean from physical harm from other people but rather from those people who absorb others' energies and leave you feeling down, tired and drained. These people are known as Energy Vampires, and most people know of at least one in their lives.
So what is shielding? Shielding is a term we use to define a shield or bubble of protection. The most commonly used method of shielding is "white lighting" or "white bubble".
Even Comic books, Cartoons and movies have depicted bubble shields, many times! This is pretty much how you would imagine your bubble shield to look.
Why do we shield ourselves? to protect from negative energies and those who drain us of our positive energy. Have you ever walked into a room or building and it just felt "odd"? or perhaps you know someone who whenever they are around you feel drained, empty and possibly angry? These are all times when shielding is needed.
Before you go putting up your protection shield, you first need to be sure that you don't have negative energy yourself. A good cleanse is always good practice and you should certainly be sure you have cleansed you own energy before shielding yourself.
Cleansing can be done in several ways, smudging with white sage, palo santo or sacred herbs and resins is most common. Ringing bells, clapping your hands and chanting are other good cleansing techniques.
Once you've cleansed your energy, it's also a good idea to ground yourself. (If you haven't already before cleansing).
The easiest way to shield yourself, is to imagine a bright white light of pure positive energy radiating around you, this can take form of a bubble which encases your body and aura in it's protection.
Other ways are visualizing a suit or armor like a knight would wear, that you "put on" other people I know use visualization to shield themselves in other ways as well. I have been throwing up walls of fire to block energy lately which has been working quite well for me.
As with all magic and spiritual practices, find what feels right for you. Each of us is different and once you have the basics covered you can work on those to adapt to your own way and find what works for you.
This is just a very basic guide to shielding, there is a wonderful amount of detailed information available online for those who need more guidance.