Well, in order to explain what's going on, I'm going to have to talk about some things that you can never see "in game." Assassinations are never "pre-planned"; they happen because somebody really hates you (I've gone through several games with no assassination attempts). Initial introductions in every system are extremely important in making people like or dislike you, but that shouldn't be too hard to interpret. However, both during system introductions and during more traditional start/end of turn events, choices and skill checks can result in favor changes among 10 factions that you are never told about (there may also be racial-wide changes). Electors are affected by these factions, so when you make a dialogue choice that upsets the xenophobes, you're creating more enemies for yourself, and you don't even realize it.
This just to say that it's extremely hard to advise you, and I'm just going to put more pressure on you, because seemingly innocent dialogue choices may lead to your demise, because an unseen faction got upset. Generally speaking, if there are dialogue choices with skill checks that you can complete, you'll want to choose those over failed skill checks.
My initial winning strategy was to have a pet viper and focus on my social skills, interaction and emotion, with emphasis on etiquette, rhetoric, allure and menace. Since blackmail was nerfed, menace is probably not as good these days, but empathy is always useful to gauge affection, so that's a viable substitute. It sounds like you're on the right track doing something similar. Don't underestimate charming someone if you can pull the allure test off, it gives a juicy affection bonus to that elector.