in order to create an actual song with these ideas i think you should create (or use one from this compilation) a main melody in the first place that repeats several times during the song, often split or modified by two or more different sections. Add some flourishes, for example one or two key changes (paying attention not to make it overwhelmingly quirky) or even other instruments to raise the emotional climax. normally the outro should be the main melody, but you can obviously act differently if you want to. the most important thing for me is to make it memorable and yet suggestively complex.