"sheilding" or "protection" can be done in numerous ways.
Mine is usually some version of the LBRP (Lesser Banishing Ritual of the Pentagram)
after a grounding visualisation.
(I'm partial to a Dianic LBRP version, that calls on multiple Goddesses - but more recently have been creeping back to speaking to those Archangels and Adonai again).
Simpler grounding and shielding - as recently re-iterated to me by a medium -
is doing that meditation where you image yourself growing roots into the ground from the soles of your feet, like a tree, and becoming firmly rooted and strong. ("grow roots down, deep into mother earth, stop at a place that has a meaningful connection for you. Feel the love, nurturing and protection that mother earth gives you" ...sort of paraphrased from Fritz Smith, Zero Balancing founder).
The Protection phase (for example) is imagining you are putting on a midnight blue impenetrable cloak, draw it firmly around yourself and tie it on. See it shielding you from all forms of "negative vibrations" if you like.
You can alternatively imagine fortifying a protective bubble around you (fortifying your aura - or biomagnetic field)...
Sometimes I lean towards a more Sci-Fi-like forcefield mirror, in my minds eye...
The burning of various scents and the carrying of relevant crystals can also be done.
I imagine "raising your vibration" is a metaphor (though some may beg to differ) in which you are choosing a mindset that is optimal for you to read and come from a place of strength (within your own belief system - I "believe in belief" as I often say

) to have
clear boundaries so that nothing interfears with your performance.
Before a reading - I have a little chant (prayer) that I devised, which puts me in the right frame of mind.
Have a look at the Threads on Magick and Ritual for this here:
http://www.tarotforum.net/showthread.php?t=242721