Actions. Lifestyle. Fellowship

  Walking through the steps of the sinners refers specifically to the actions. The activities that the wicked do. The next part of the first verse which is "stand in the way" means their lifestyle. The previous line might be an immediate action but also can mean some major plans or goals in life. Whereas "standing in the way" covers a more broader sphere such as lifestyle, conduct, journey, outlook, and perspective. It's their "way" of life. Then the last part represents the companionship or the fellowship of them. The activities, lifestyle, and companionship of the sinners. Blessed is the man who turns away from those.

The Psalmist continues to describe that kind of man on the second verse telling on what he's up to. After avoiding the dark side he ought to be doing something else. His delight or joy is only found in the word of God. He reads it. Ponders it. Devote his time on it. On a regular basis. This is what he loves to do. The psalmist gives us the picture of a well-nourished tree that keeps on producing fruit. That person like the tree is prosperous on whatever he intends to do. Contrasts it to the wicked which is weak and just become unsuccessful in life. Full of failures, disappointments, hopelessness, even frustrations. 

"For the Lord watches over the way of the righteous,
    but the way of the wicked leads to destruction." - Psalm 1:6

In the final line of the chapter, the author planned to give the credit to God. He assures the readers that God watches the righteous person. God makes sure that he is taking care of unlike the wicked person that only can receive destruction.