1. Give praise and affirmation - 

The tongue has the power of life and death - Proverbs 18:20

"Comfort, comfort my people, says your God.
Speak tenderly to Jerusalem and cry to her . . ." - Isaiah 40:1-2

I know that ultimately God must be the one who affirms my wife, children, friends and family.  That knowledge however, should not cause me to be become apathetic in my praise of others.  Such knowledge should rather drive me into being a more uplifting individual since I realize that it is of God to encourage the weak and fainthearted.  Joining him in his mission is sure to draw me nearer to him and his kind and gracious character.  I get to experience fellowship with my father God when we work together through my speech.  Furthermore, when some does arise that requires confrontation the addressed individuals will realize that God does not only speak when he is angry but all of his words are words of love.  Some are of forebodings of wrath while others are messages of affirmation, kindness and goodwill.  Let us then who speak speak as if uttering oracles of God.

2. Praise and affirm publicly - 

"a voice from heaven said, “This is my beloved Son, with whom I am well pleased.” - Matthew 3:17

If God thinks it is good to affirm and praise in front of others then it is safe to say that public affirmation is a very good thing.  It not only strongly affirms the one who is praised but it also motivates others to act in such a way as to receive similar praise.  I think if I heard God saying to a man as he died "well done good and faithful servant!  Enter your father's rest" then I think I would be pretty motivated to impersonate that man's faith.  In the same way when we see someone doing something well and faithfully we should praise that person.  Don't just take their helpfulness for granted.  Praise them and do it sometimes in front of others so that those people will also be motivated on to good works.
(In marriage praising your spouse publicly highly affirms her.  It stirs up other wives to live well.  It stirs up other husbands to also praise their wives.  It also stirs up young people to seek to live in a manner worthy of such actions)

3. Repeat -

"Therefore I intend always to remind you of these qualities, though you know them and are established in the truth that you have. I think it right, as long as I am in this body, to stir you up by way of reminder, since I know that the putting off of my body will be soon, as our Lord Jesus Christ made clear to me." - 2 Peter 12-14

Many difficulties in marriage find their source in the fact that things which were once said are not often enough repeated.  Words of love and affirmation are lost in the haze of memory and after too much neglect some marriages break apart for lack of better communication.  But in this passage and many others the Bible clearly emphasizes the need for repetition.  The fact that Philippians 3:1 and Jude 1:5 repeat this point just confirms the need for us to be continually stirred up by the repetition of things we already know.  The doesn't mean that we just keep repeating the same mundane mantra.  We should be focused on the future and the development of our relationships into new realms.  But we cannot forget to repeat the stories and truths that have brought us to where we are.  Otherwise we build upon a crumbling foundation or become like a growing tree with rotting roots.  Our stories and history help set the course of the future.  
Knowing is not enough we must remember!