As one of the most important verses in all of Jesus' teachings, this verse is often used in quotes, artwork, and Bible memorization. God's kingdom and righteousness require that one lives in a continuous state of repentance from sin and live the dedicated-to-God lifestyle that Jesus has described. We can trust that God will provide for whatever it is we truly "need" in order to accomplish His purpose.
We are invited by God in His grace to live a life unburdened by worry and anxiety. We are invited to seek first the kingdom of God and the righteousness with which we are clothed when we place our trust in Him for salvation. The first thing we should be concerned about is God's kingdom. When we have the right priorities in place, all of those other things will become available to us as well. Otherwise, worry and fear can cause a believer to spiral downward into despair.
However, He understands that we have daily needs. As we trust in Him, He makes many precious promises about providing all our needs and supplies all the necessities of life. Thus, as we rely on Him, we just need to remember that He is able to do far more abundantly than we could imagine.

Dear Heavenly Father, I know that too often, my lack of faith in Your promises has led me to pursue the things of this world by myself. It is a lack of faith in You I confess. Please help me to put Jesus' words into practice every day and make Him the primary focus of my life. Please allow me to seek Your kingdom and righteousness as my first priority from now on, knowing that You are my great provider. 
In Jesus's name I pray. Amen.