Post History
The first answer to your question, as everybody else is pointing out, is research. Anything you don't know about, research. Read about it to get a general picture. Look for first-hand accounts (peo...
Answer
#4: Attribution notice removed
Source: https://writers.stackexchange.com/a/39333 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#3: Attribution notice added
Source: https://writers.stackexchange.com/a/39333 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#2: Initial revision
The first answer to your question, as everybody else is pointing out, is research. Anything you don't know about, research. Read about it to get a general picture. Look for first-hand accounts (people you can interview, youtube, written accounts). In particular, note when first-hand accounts differ one from the other - you want to know what's always true, what's true most of the time, and what's rare but can still sometimes happen. In your research, take note of small details. It's the little details that make a story come to life. For example, if I write about two glass-wearing characters kissing, I might have their glasses collide, creating a moment that's awkward and human, and particular to my characters, rather than being yet another couple kissing. Or, if a character is nervous, I would consider what they're likely to have in their hands in the time period I'm writing about, and have them play with that. (I've done my research - I've observed nervous people, myself included, play with pens, bracelets, etc. when they're nervous. Now I cast a character in a similar situation, and convey their nervousness by way of the detail.) And yes, research includes observing yourself. The fact that you've experienced something doesn't necessarily mean you've actively observed yourself experiencing it. Though that's not exactly on topic for you. :) Research alone is not enough, however. Try to put yourself in your character's shoes: what would you do in their situation? How would you feel? How would you act? Not just in a momentarily situation, but having lived their life, their background, how would that be affecting your worldview? Notice how background affects the kind of choices a character could reasonably make - that's going to help you. When you read a book or watch a movie, roleplay the scenario in your mind - how would you feel and act? How is the characters' backstory affecting their choices and their feelings, their perception of the situation? (Are they, perhaps, acting "out of character", in ways that serve the plot, but do not represent the way they would reasonably act? Being a critical audience is also helpful and interesting.) You speak of specific experiences - drunkenness, drug use. But the thing is, a barely-legal boy who's never been drunk before getting stupid on free beer is going to be very different from an adult who's down on his luck and drinks to forget his sorrows. Their whole experience of the situation, and of drunkenness, is going to be different. Alcohol reduces inhibitions. But what happens next? That depends on the character - what kind of person they are. What is it that they would have liked to do, if it weren't for inhibitions? Go talk to that girl, or go rape her? Same with drugs - different drugs, different reasons people take them, different effects those same drugs have. The "down" after the "high" is also different, and so are the consequences. In fact, I'd say the "trip" isn't all that interesting, most of the time - coloured blobs, bunnies, whatever. It's the before and the after that are interesting. That's when the character is making decisions and facing consequences. With research, that should be easier for you to imagine than the actual sensation of drugged weirdness.