If we want to be having the right kind of thoughts, we should commit our works to the Lord (v3). If we want peace, we should make sure our ways please the Lord, and then we don't even have to worry about our enemies because they'll be at peace with us (v7). If we want to be happy, we should make sure to be trusting in the Lord (v20b)
Our way might seem clean or right, but the Lord sees a lot deeper; And "our way" leads to death (v2,25). Pride goes before the fall (v18). We have our methods of figuring out what to do, but if we really figure out what to do, that's from the Lord (v1,9,33).
Righteousness is more important than riches (v8,16,19). This chapter says several things about kings, and righteousness is important for them (v10,12-15). Righteous and pleasant speech is important (v13,24).
Here are several other things I noticed in this chapter. Verse 29 reminded me of a recent local news story about people who broke into a house and accidentally beat up the wrong guy instead of the guy they meant to attack. Verse 28 tells us another thing about what causes strife to spread and grow: A perverted or deceitful person. And before we whisper or speak in secret, we should think twice about why we are.