When I was first starting out I wrote everything about everthing in my BoS on the elements. Here is a sampling on the element of Earth: ( I find this list of attributes most help when trying to meditate on an element and it ritual writing)
Gender: Feminine, Passive
Color: Green
Time of Day: Midnight
Tarot Suit: Pentacles
Qualities: Understanding, Stability and Strength (legal matters too)
Animals: Bison, Cow, Stag...
Metal: Iron
King: Ghob
Archangel: Auriel
Spirits: Gnomes
Jewel: quartz, salt
Places Ruled: caves, chasms, fields, groves....
Musical Instruments: Percussion( including piano)
Astrological Signs: Taurus, Virgo, Capricorn
Hidden Knowledge: Secrets
Magic Skills: Money, business, death, binding rites, food
Sense: Touch
I hope this list of associations can help deepen your meditation and add variety to your spell and rituals
-JenJen