I think that one of Thatcher's strongest leadership qualities was a sense of political savvy. She recognized that aligning her philosophy with that of American President Ronald Reagan would not only help her in the short term, but it would ensure that history would smile upon her. Thatcher recognized that Reagan was a unique leader whose philosophy was to demonstrate a complete sense of brazenness in political decisions and actions. This "all in" approach was something with which Thatcher aligned herself and it proved to be successful for her and England.
Another political trait I think applies to Thatcher is her ability to unite the masses under one common banner. The nationalism that Thatcher invoked appealed to Britons on a mass scale. It was under this cloak of national identity that Thatcher was able to engage in foreign endeavors such as the Falklands Crisis and not have to take much of a hit politically for she linked it to nationalism. At the same time, it was under this guise for nationalism that she could afford to either deliberately or unintentionally ignore the plight of ethnic minorities in England. Artfully, she was able to shift the focus on them, indicating that a lack of support of her administration essentially amounted to a betrayal of England under nationalist ideas.
Finally, I think that one has to credit her with an ability to quell dissent. Thatcher took on the trade unions and silenced them fairly effectively. Her brand of capitalism stressed individual work ethic. Her resistance to European unification was driven by the idea that she argued it would decrease British sovereignty. In the end, she was able to use her force of leadership and charisma to quiet dissenters and the voices of opposition in many different realms. In a political scene that focuses on such voices like the British one, this ends up becoming quite an accomplishment.