There is no difference between the Hebrew word for desire and the Hebrew word for covet. Coveting means desiring something too much. And too much is measured by how that desiring compares to desiring God. If desiring leads you away from God rather than closer to God, it is covetousness. It is sin.
I suspect that the reason the Ten Commandments begin with the commandment “You shall have no other gods before me” (Exodus 20:3) and ends with the commandment “You shall not covet” (Exodus 20:17) is that they are essentially the same commandment. They bracket the other eight and reveal their source.
Not coveting means not desiring anything in a way that diminishes God as your supreme treasure. And not having any gods before God means the same thing: Don’t treasure anything or anyone in away that competes with God’s supreme place in your life. Idolatry is what we call disobedience to the first commandment. And idolatry is what Paul calls disobedience to the tenth commandment (Colossians 3:5).
… But how, Paul? Do you have a practical suggestion that we can use to fight for this satisfaction in Christ? Here is what we saw in Philippians 3:17, and it is striking: “Brothers, join in imitating me, and keep your eyes on those who walk according to the example you have in us” (Philippians 3:17).
Here is amazingly practical help for us: Pick out some people whose lives show that they treasure Christ above other things. Then “keep your eyes on them.” Watch them. That, Paul says, is a good way to conquer covetousness.