I think the best way to summarize Ponyboy's personality is to say that he is very loyal to his friends. He is quite supportive of them. We can see this especially in how he deals with Johnny. He helps him deal with his unhappy home life, for example, and he tolerates Johnny's fears that come from being beaten.
With regard to his life, he is not pleased with how his life is at the moment but he is, especially at the end of the book, hopeful that he will be able to change things and get a better life. This is symbolized by his writing assignment -- he stops being hopeless and gets started on writing his theme.
Ponyboy's personality towards his friends and his life has a big concept on trust. They trusted each other from the start and to the end of their lives [assuming they'll continue to be in the gang called greasers]. Ponyboy's personality to all the member of the gang are pretty much the same, equal
Ponyboy's personality especially towards Johnny is love. He cared and trusted him so much that when he died it made him think that he never did. That made him think Johnny was still inside of him, until the end when he read the note from Johnny. The note said to live on and show Dally sunset [Of course Johnny wouldn't know that Dally died after he died]. After he read that he let go of his thought and continue with life. I don't know if you will consider his brother as a friend but in the book he did say he loved Soda the most. Soda would usually stick up to him when he was in trouble. The problem is Pony doesn't know what Dally gave up on in order for Pony to be the way he is. He gave up his scholarship which meant his future just to take care of Ponyboy. Later on he'll soon find that out and love each other
So I think Ponyboy's personality towards his friends and to his life is very caring and loving.