After doing longer campaigns for a while, my group is now getting into a series of one shots to try different settings, systems and overall experiences.
What I realized so far when playing one-off games is that I often have trouble getting "into character" quickly, even if I do like the concept or idea behind it or try to model them after a character I know from a TV show or something. It's like I just need more time to get to know this person in order to feel comfortable playing them. On the other hand, I don't want to end up falling back to character concepts I feel familiar with, as the whole idea of the one shot marathon (for me) is about getting out of our comfort zone.
I'd really like to take this chance to explore different concepts and character ideas, as I usually end up with similar-minded PCs - it feels like in the end, I am falling back to playing "me", especially when the character is new and unfamiliar.
Are there any techniques (maybe from theatre/improv/acting) to get into character more easily? Can playableness already be addressed during character creation, and if so, how? What can I do during a game session to make sure I'm roleplaying a defined character and not falling back to do what "I" would probably do?