Ps 1

1 Blessed is the man that walketh not in the counsel of the ungodly, not standeth in the way of the sinners, nor sitteth in the seat of the scornful.
2 But his delight is in the law of the Lord; & in his law doth he meditate day & night.
3 And he shall be like a tree planted by the rivers of water, that bringeth forth his fruit in his season; his leaf also shall not wither; & whatsoever he doeth shall prosper.
4 The ungodly are not so: but are like the chaff which the wind driveth away.
5 Therefore the ungodly shall not stand in judgement, nor sinners in the congregation of the righteous.
6 For the Lord knoweth the way of the righteous: but the way of the ungodly shall perish.

in verse 1, the way i interpret this is: we are given instructions not to keep company with the ungodly, the unbelievers, the sinners. we don't want to treat them unkindly, we just don't want to hang out with them. satan uses them to influence. keeping company with them may influence us to do or say things that are inappropriate for christian behavior.
in verse 2, we are to delight in the Lord & his laws. we're to meditate on them all the time.
in verse 3, if we do this we will be planted in good soil & be fruitful. we will prosper in all that we do.
in verse 4, the ungodly are like chaff (refuse, worthless matter that can be light & driven away by the winds)
verse 5 i'm not real sure on but, it seems as though the psalmist is saying that the ungodly will not stand in the same line (so to speak) as the righteous or be judged as we because they will be cast out.
verse 6, because the Lord knows our hearts & the hearts of the ungodly. therefore the ungodly will never see eternal life.
How wonderful for christians yet, how sad for the ungodly. In the grand scheme of this, God really doesn't ask that much of us. He's given us the gift of salvation & just wants us to do our best to follow his commands. Many times, earthly parents & other authority figures expect more of us than this. What is so hard about loving God, being faithful to him & trying to follow his commands? If you remain in Christ each & every day, he is always there with you to assist you.