in my Being an Empath post this was mainly my question also. How to efficiently shield.
I've been given suggestions-a-plenty over the years,
visualizing the violet bubble, a violet light blanket surrounding me & my family, after having done meditation and cleansing and super focusing. Affirmations of 'being like a duck' ... rolls off me like water.
there are actually a few good youtube videos out there to help for this.
for myself, I'm not very good at it. My own fault. I'd need to do this daily, and I guess it's a lack of commitment or laziness that distracts me, something I need to work on.