I think education is a huge factor. Anecdote: I took human sexuality at university. We had pop quizzes daily. For quiz on birth control someone comes in and states, 'Oh I didn't need to study for this, I've been using birth control since I was 16' They failed the quiz.
Honest communication is a huge factor in prevention. My current girl friend let me know early in our relationship she had chronic hepatitis B. I'm in process of testing for my own exposure, and will get vaccine if needed.
If you're not 100% sure about your history, get tested, lots of stuff can be asymptomatic. Some healthcare systems offer free testing for some diseases.
Isn't STD Sexually Transmitted Disease a bit of a misnomer? While sex might be the primary method of transmission, from the article CDC attributes increased drug use as one of the factors. Or am I just being pedantic?
additional info: I'm definitely not young anymore.