Watch the Develop the Hook online guitar lesson by Ravi from 1-2-3 Songwriting
For this approach I am assuming that you already have a line, and that is your starting point. If you don't, make sure you keep a little book of ideas - things you overhear or pop into your mind. Then, you can go back to that book and pull out hooks to initiate your songs. Write your line at the top of a blank piece of paper. Now, start exploring the meaning of it and think about what feelings it inspires. This will determine the mood of the music that you want and help dicate the most appropriate chords and progressions. Put some chords under your words and make up a melody. Try to emphasize the key words in your phrase by choosing the most impactful melodic notes and support them with the most appropriate chords. Think about the rhythm of both your words and music, making sure that phrasing is natural. Really dig into the meaning of your words because the art of a good song is to have consistancy between the meaning of the words and feeling of the music. As your hook comes together, extract the title. Pull all that together and check it off your list!