Psalm 18 describes in pictures how God works. David didn't see God. David only saw how God gave him help. There are 6 parts that this Psalm can actually be divided :
Part 1 - God is a Rock for David
Part 2 - David asks for help
Part 3 - God answers David
Part 4 - Why God gives help to people
Part 5 - Everything that David owns comes from God
Part 6 - God made David king
Psalm 19 is about words.
Verses 1-6 Nobody speaks any words but we see all that GOD has created. (Nature)
Verses 7-11 God's name becomes LORD and the use of this word to describe the time when
people decided to follow God. He becomes their LORD.