The Five Elements Alliance is a school I've done a lot better with lately. As you maybe can guess they're themed along the five elements: Wood, Fire, Earth, Metal, Water. (Blank) Spirit effects are triggered if the previous card was in the same element or if you are playing them in the Generating order. Which is the order I listed them in above. Each element plays well with itself and usually has something that plays well with the generating element, but some moreso than others. Wood->Fire synergize very well but Metal->Water doesn't have much going on.
I think I usually see mono-Earth (which just stacks defense to the heavens), mono-Metal (which results in big damage boosts), Wood->Fire (Both share multi-hit attacks and Increase ATK buffs for them), Earth->Metal (A metal card gets buffed based on your defense), and mono-Water. Order listed is in no way indicative of metagame share.
Water's gimmick is Force of Water which dings the opponent for one point per stack at the end of your turn, which is cute when it's an extra singular point of damage a turn at the start of the game and your opponent starts dying hard when it turns into 20 or 30 points. Dive was also quite powerful in that specific game as several players were on this Sword Intent one-big-attack plan and Dive taking 40% off those hits let me almost exactly survive long enough to beat them.
However as you can see I came in 2nd, because the winner had a very fast deck that did not actually have to attack, which meant all my "Dive to reduce attack damage and Combine Rivers to heal up again" was for naught. Still a positive result!