Well my sheilding spell is somewhat different to yours in outlook... the technique is the same for raising the energy, I just had problems with he pearly/mirror bubble.
I experimented with several different things and finally figured on a silver sheen that sits over myself like a bodysuit (ooeer), I can make it mirrored at will though it is easier to incorporate it into the actual spell to begin. My protection can be gold for when I am feeling threatened, silver for when I really know the shit will hit the fan and mirrored when I want to reflect the bastard negitive energy right back at the A$$hole sending it at me.
I must admit although I dont wish badness on anyone or cast spells to harm I feel no remorse anymore about reflecting bad crap right back at a person, I spose its the mindset of you get back what you give...
I am a forgiving person but my forgiving only goes so far before I let the individual dig their own grave.
I will never attack only defend, but then how do you know your not overdoing the defence a bit too much, when I get angry it tends to taint my magic somewhat and I can almost taste the magic being adversly effected.
The next thing I spose I need to do is concentrating on meditive and calming proceedures before casting.