This is a quickie in answer to a specfic question of a student. But I hope there aren’t too many typos and so on, and that you can enjoy and understand it.
Cardinal mode has similarity to fire.
Fixed mode has similarity to earth.
Dual mode has similarity with air.
Water has some similarity with all three modes – a little bit like each.
However, the context you have to remember is that every element mixes with every mode, to create the twelve zodiac divisions.
Aries is most “cardinal” (decisive and independent) of all the cardinal signs, because it is cardinal and it is fire, an element that has a lot of similarity to fire. Nontheless there are other fire signs too. Leo is the fixed fire sign. The decisiveness and independence is thus mixed with loyalty, confidence, and stubborness. Sagittarius is the dual fire sign – so the decisiveness and clarity of fire is mixed with the egalitarianism and broadmindedness of the dual mode.
Taurus is the “most fixed” of all fixed signs – the most stable, reliable and strong, because it’s element is earth – which has a lot in common with the fixed mode. Capricorn is also an earth sign, but it’s cardinal. It is “decisively stubborn, and independently strong and reliable.” Virgo is also an earth sign, but it’s dual. It is practical like the earth, but not stuborn because duality makes it egalitarian and more unsure and pensive.
Gemini is the “most dual” of all dual signs – it takes many different points of view, and stays on both sides of every fence – because it’s element is air, which moves about and thus has a lot in common with the dual element. But Aquarius is also an air sign, yet it’s element is not dual, it is fixed. So Aquarius is patiently and reliably moving about collecting experiences in it’s pot. And Libra is also an air sign, yet it’s element is cardinal, so it is much more adventurous and ambitious about the ideals of air – to roam free and experience life pleasantly.
It’s not easy to say which of the three water signs is the “most watery.” Cancer is cardinal water – so the emotions and introspective nature are quite strong. Scorpio is fixed water, so the emotions and introspective are stubborn. Pisces is dual water, so the emotions and introspection are all-encompassing, they affect everything and create indecision.