The first step you should take is to form a strong thesis statement for the introduction of your paper. Your thesis statement should include: 1) an assertion about alcolhol and advertisement toward youth and 2) three subpoints that support or explain your position.
Cause and effect-- Increased youth alcohol abuse has been increased by advertisement. Create three subpoints that show various ways advertising targets the youthful audience.
Relation-- Create a strong thesis in which you assert that alcolhol advertisements target youth; your subpoints could be various examples of advertising that target youthful audiences. Then in your body paragraphs you could further analyse the advertising.