"Do not be anxious about anything, but in every situation, by prayer and petition, with thanksgiving, present your requests to God." (Philippians 4:5)
I think with this verse it will be easiest to take it section by section.
"Do not be anxious about anything . . ."
Paul is talking about the same thing here that Jesus taught about in the Sermon on the Mount in Matthew 6:25-34 - the futility of worrying about things. We're not really living if we're worrying or anxious about things. And we have no reason to be.
". . . but in every situation . . ."
There's no situation excluded from what Paul is talking about here. It covers everything.
". . . by prayer and petition . . ."
Prayer is talking to God. Petition is asking of God. Both are important in our relationship with God. He wants us to communicate with Him.
". . . with thanksgiving . . ."
Thankfulness should be a regular part of our lives. No matter what we're facing in life, we can be looking for things to be thankful for. Being thankful changes our perspective on things.
". . . present your requests to God."
This is Paul's answer for how we can avoid being anxious and worrying about everything. We can take all of those things to God and leave them in His hands. God invites us to bring those things to Him.
Are you worrying about things?
Are you taking every situation to God?
Are you looking for things you can be thankful for?
Are you taking everything to God in prayer?