Prov 4 v 6 - 7: Do not forsake her, and she will preserve you; Love her, and she will keep you. Wisdom is the principal thing; Therefore get wisdom.
For me, this is the theme throughout this chapter.
A brief summary
Firstly, more benefits are noted:
v6: She will preserve you
v8: Exalt her, and she will promote you
v10: The years of your life will be many
v12: Your steps will not be hindered
Secondly, some wisdom is offered: v14 - 17, do not enter the path of the wicked.
Thirdly, v 23 -27, keep/guard your heart. These verses are full of practical advice and admonishments, firmly stated.
v6: Forsake not wisdom, and she will keep, defend, and protect you; love her, and she will guard you
v23 Keep and guard your heart with all vigilance and above all that you guard, for out of it flows the springs of life
What have I learnt from Prov 4?
It almost seems like Solomon is writing with an urgency. You can feel how important this is to him and how passionate he is about Godly wisdom. And rightly so. Its written so directly and practically you cannot fail to get the point. I believe the principle points are: 'give attention to my words' and 'dont forsake her (wisdom)' and 'do not let my words depart from your sight'.