Have you ever felt vulnerable or that someone or something is making you feel emotionally or physically uncomfortable? Whether it is from someone you know or a total stranger you passed by on the street, have you ever felt them in your personal space without your consent?
There are actually some exercises that can be done to help protect and contain your energy. Visualizing and imagining are beautiful simple tools that can be practiced daily to help enforce that calming, protective energy.
Some of these practices could be using your visual imagination; imagining a bubble of light or putting on a belt of mirrors or zipping up your aura which is a few centimeters away from your physical body. Drawing a circle of white light, putting all your intentions into it (what you want inside it and what cannot enter) and then walking into it then expanding all around you into a bubble. It is up to you how big you want your bubble to be and how much distance you want between you and your shield. I personally suggest a good arm's length.
Other practices could be invoking certain emotions or sensations; feeling wrapped in a warm blanket, feeling protected by God or calling upon a particular Saint or Angel. This protection and shield gets easier to create, the more you practice and link to certain movements or prayers or even exiting your house. Whenever I feel unsafe I find myself either putting my hand to my belly (solar plexis chakra) or to my heart (heart chakra) and I physically feel the warmth of my hand and say a prayer while imagining that I am literally covering or protecting my energy.
The way to reinforce your shield and heighten it's vibrational energy is to connect to God/spirit. You can do that by saying protective prayers and verses and trusting in God/spirit to protect. Use whatever you can sense to help you link your shield to that particular scent, image, prayer, sound, feeling...etc be creative and believe.
The more you practice the more you will be conscious of energies and your personal power/space. The more grounded and protected you will be. You can even begin to extend your shielding to other persons regardless of where they may be.
Be safe, Be compassionate, Be...