Psalm 63 is a lament offered with confident expectation.  The idea is to develop confidence in God during times of trouble.  David probably wrote this Psalm as he was fleeing from Absalom.  

1-2 – David is apparently inflight and unable to worship at the sanctuary, so he remembers past worship at the sanctuary.  His soul thirsts and his flesh faints for God.

3-4 – David is confident of future worship in the sanctuary.  David anticipates singing, lifting his hands, and praising God.

5-8 – Yet, David states he clings to God wherever he is, even in the watch of the night because God is his help.

9-11 – David then in confidence declares that those who seek his life will fail and die.  As a result, David will rejoice in God.