Do the Research
Perhaps one of the most enjoyable aspects of writing a story or novel is the research that goes into the process. You can choose to get some hands-on research by going to a bar and observing patrons, or you can play designated driver to your friends and see how different people act while intoxicated. You might notice some people become affectionate and like to hug or express feelings more openly when they drink. Others might become hostile or belligerent after having one too many; Scientific American points out a research study from the Journal of Experimental Social Psychology in which drunken participants were much more aggressive than their sober counterparts. Seek out research studies like these to get a deeper understanding of how people behave while drunk.
Making Decisions
Make a list of the types of drunken people you encountered or read about in your research, and outline characteristics of these individuals. The obnoxious drunk, for instance, is loud and might say things, often inappropriately, without thinking. The sad drunk might lock herself in the bathroom to avoid people, and cry by herself. The fighter drunk will start arguments or fistfights with anyone. Choose one type of drunk, and delve deeper into that character's persona. Consider if he has underlying mental health issues that drive him to drink. Think about how many drinks it might take for your character to get drunk; the Mental Health Foundation suggests three to four drinks for men or two to three drinks for women is enough to cause intoxication. These details will come in handy when you're writing your narrative.
Asking Questions
After writing down ideas about the drunken side of your character, ask yourself questions to highlight other aspects of your character's personality, for example, a drunken character might use drinking to hide that she is desperate for love and stability. Consider how your character's drunken behavior is more than just a character trait, and how drinking defines the character's life and actions