What does Psalm 5:3 mean?

David began each day by praying with the assurance that the Lord heard his voice. He prepared his prayers as sacrifices to God. Israel's priests prepared animal sacrifices by placing each piece of the animal in order upon the altar (Leviticus 1:8) and by placing the loaves of bread in order on the table in the tabernacle (Leviticus 24:8). In his own way, David carefully arranges the parts of this prayer, in order, before the Lord. Prayer does not have to be rigid, formal, or mechanical (Matthew 6:5–8), but neither should it be haphazard. If we use the example often referred to as The Lord's Prayer in Matthew 6:9–13 as an example, we find several significant components. The prayer includes adoration, submission to God's will, petition, confession, and a plea for guidance.

David adds in Psalm 5:3 that he not only prays but also watches. He was consistent and expectant watching for an answer to his prayer, symbolized as a guard on a watch-tower diligently watched for whoever was approaching.