mmm to be Empress of the Romulans well I guess if your serious.
1. Get the Federation Captains to like you and trust you.
2. Be ruthless and assassinate your rival.
3. Denounce logic being superior to emotions
4. List all your rivals affections for the Klingon species.
5. Having human in you is a plus.
From what I read and observe in TNG when it came to Sela she is a master of manipulations both using logic and emotions. Sela is not dangerous because she is emotional but because she can use logic as tools further her agenda. I am not the most social creature but Sela is and to her the fact she uses observation of her opponent in negotiations is superb. Most of the Emperors I observe are not exactly stupid and make great tacticians.