"Other than that, I'd watch some TV shows. Game of Thrones, obviously, is a good one. Here are some others, with an eye towards watching people within negotiate each other and the political landscape around them:
If you've already seen them, rewatch a few episodes, looking specifically to create a map of how the characters interact and how their goals intersect....
To be honest I haven't seen any of these shows yet including game of thrones! Though I did srart the books. but I'll make sure to get around to it. Edit: have not figured out how qoutes work in the messageboards
While I can't ofcer gou advice on skulls and shackles I would use solo play to try a characted that wouldn't work with a group. Like a stealthy rogue/illusionist because no one wants to wait while that character is sneaking through the entire dungeon or otherwise finding unusual solutions. But for solo play it would be great!