Beatitudes

So, today’s gospel spoke of the beatitudes.

Blessed are the poor in spirit: for theirs is the kingdom of heaven. (Verse 3)
Blessed are the meek: for they shall possess the land. (Verse 4)
Blessed are they who mourn: for they shall be comforted. (Verse 5)
Blessed are they that hunger and thirst after justice: for they shall have their fill. (Verse 6)
Blessed are the merciful: for they shall obtain mercy. (Verse 7)
Blessed are the clean of heart: for they shall see God. (Verse 8)
Blessed are the peacemakers: for they shall be called the children of God. (Verse 9)
Blessed are they that suffer persecution for justice' sake, for theirs is the kingdom of heaven. (Verse 10) 

My question is, how can we obtain these blessings properly? Some seem obvious.

How can we be more poor in spirit? How can we be clean of heart when it’s so easy to dirty up?

Poor in spirit:
authentically humble, sincere and single-minded in our love of God and other people

silk.net/RelEd/beatitudespoor.htm

The pure in heart:

catholicculture.org/culture/library/view.cfm?id=7438

Catholic Encyclopedia: the beatitudes:
newadvent.org/cathen/02371a.htm

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