Praise is often linked with thanksgiving. You are praising God, which includes the acknowledgement of His power, grace, sovereignty & authority. Praise songs are bubbly and upbeat. When we sing praises to God, we are joyfully describing what the Lord has done for us. We can praise God in many ways. Here are a few from the bible:

While praise can be given to anyone (eg. you can give praise to your friends & family), and is a celebration of works, worship is devotional. Worship is a total surrender and attitude of the heart. 

Worship isn’t offered to anyone else but God (Luke 4:8). Worship is relational – you are baring your spirit before God and receiving His own Spirit. It is very intimate. Though we often sing and utter words when worshipping God, it is also important to be quiet so you can hear God – listening is important in worship (Ecclesiastes 5:1-2). It should not be a monologue, but a conversation!