Time to revisit Baneful’s Column.  There is a concept that’s universal amongst all card games: excessive greed being bad.

(Greed – From Magic the Gathering)

A trap that many beginners fall into is trying to go for extremely powerful cards (i.e. high cost cards, cards that generate a ton of value over a long time).  Greed is okay sometimes, but for the most part, you want consistent and reliable.

You don’t want cards that are great if you’re already in a comfortable position.  You want cards that can turn around a tough match.

Think of all of your games as a spectrum.  Some games are lucky.  Some games are not lucky.  And the rest are skill.  Cards that make you win more when you’re already going to win serve no purpose.  Instead, it’s better to build decks to swing those critical matches in the middle that can go either way.

In most cases, cards which are useful on the turn they’re played are best.  Especially in games where removal is common, they may not last long.  This is also true because you have to address the opponent’s board state.  If they have scary things on their board, you have to contest those things and don’t have the luxury of playing a card that takes too long to get value.