I use the visualisation for psychic protection and to draw emotional strength from it. It's not a particularly special visualisation; a classic Arthurian based one.
You are kneeling in front of an altar, it is dark & stormy outside but there is a single candle lit upon the altar (in my youth the altar was in a typical church but now the church is roofless and romantically ruined). It sits within a green wood grove, verdigris with moss, where ferns are growing out of the stones walls and multi-coloured lichen cover the stones. The storm is outside the grove. You are wearing full plate stainless steel armour, that is polished until it gleams like silver. You are holding the sacred sword, Excalibur, point down in front of the altar. A knights shield is upon your back polished to become a perfect mirror. Stare at the flickering light of the candle which reflects spears of light from the sword and armour. On a long and deep in-breath draw the light from the candle into yourself. On a slow out-breath let the light fill you until it overflows into your armour, sword and shield. You have become the light and within you is the power of the pure paladin - nothing can break this defense. The light gleaming from your armaments holds back the dark. You are safe.
I then bring my consciousness back. As I've been using to for a long time it's ingrained & I can complete the visualisation in a single breath cycle. I normally touch wood to ground myself and bring a little luck