Keep your points system as simple as possible. Make it easy for user to quantify how much their points are worth so they can understand the value of it.

 

Earn 1 point for every $1 spent

For place order, opt to use 1-to-1 points system. This way, customer can easily know how much points they can earn from their purchase. This is important because say if a customer "aims" to unlock a reward but lacks points, they can easily deduce how much purchase they need to make in order to make-up for required points.

At the same time, it also allows customers to easily know how much each reward is worth. For example, if you have a $10 off coupon that requires 500 Points. Customer can easily deduce that spending $500 gives them $10 off their next purchase.

Many retailers like Starbucks who've previously used uneven points system (2 Points for $1 Spent) have now switched to a 1-to-1 points system.