Ha! I can be a bit of a villain in real life, so it’s not as difficult as you might think. I find it really easy to ‘think’ my way into another person’s mind-set, so I can attempt to understand their train of thought and their motivations.
In The Moon Rogue, there are a number of potential villains, so it depends on what kind of villain the character is. Krodge is a villain because she treats Emmy so badly, as is Mr Bose for the same reason. The more obvious ‘villain’ character is Bandim because of his actions towards Mantos and the empire, but in all honesty, none of them are THE villain.
No one is completely bad. I think there is good in everyone, even if it’s just a tiny smidgen of not-quite-so-bad-ness. I don’t like to write straight villain characters because they aren’t believable. Krodge has her inner not-so-bad-ness (let’s not go so far as to call it ‘goodness’) and Bandim isn’t a black and white character. He starts in a field of grey that becomes murkier as the novels progress.
A good villain is hard to write. A great character is even more difficult, but ultimately, that’s what I aim to write.