1 Thessalonians 5:16-18. Rejoice evermore. Pray without ceasing. In every thing give thanks: for this is the will of God in Christ Jesus concerning you.
These three verses have some pretty simple commandments but some precepts that are very hard to live by. Starting with rejoice evermore, we should always be ready to rejoice. We need to be glad about the things of God and the people of God. You need to rejoice when things are going bad, you are in the middle of trials, and nothing seems to be going your way. That is when God gets the most glory.
You also need to pray without ceasing. If you lead a prayerful life, not just a time of prayer, you will find the day goes better. Being in constant fellowship with the Lord will get you through each day. The Lord likes for us to talk to him all the time. He also wants to fellowship with us in that still, small voice. Praying without ceasing involves having an attitude of prayer at any time. It is a lot harder to sin when you are praying without ceasing. Never quit praying.
Last of all, we always need to give thanks, for both the good and the bad. Having a thankful heart is a contented heart. You are happy with whatever God gives you. Do you thank God for everything he has given you and brought across your path? Godliness and contentment go hand in hand. Thankfulness is the outgrowth of a contented heart. Rejoicing, prayer, and thankfulness all go together. When you have all three, you have a godly, happy Christian who is walking in the Spirit.