Praise the Lord whether you feel like it or not. Usually if you do not, you are a little depressed or unhappy, in trouble! I have had some of the biggest breakthroughs when I began to praise when I thought I couldn't. If you are wearing the garment of despair, put on the garment of praise! Let praise music fill your house, let praises to the Lord God fill your heart and spill out of your mouth. Humble yourself before God, think on Him. Think about His splendor and glory. Think about His Majesty and Omnipotence. Thank Him for all that he's done for you, for all that He is. If you are uncertain you know what praise is...are you sincere? Do you mean what you say? "Lord, You are beautiful, Lord you are..." Did you mean it? Then that's praise!
Because we love Him we want to praise Him!
Because praise to God breaks the spirit of heaviness!
Because if we don't praise Him, the stones will rise up and praise Him!
Because we want to please Him, we want to praise Him!
Because we want to express our gratitude and acknowledge His Mightiness we praise Him!
Because He is worthy!!
Pick up the Bible and look at the Book of Psalms. It has lots of examples of praise.