(1) Fire Salazar and all of his epigone underlings at Interior who continued past administrations' corrupt policies of refusing to regulate permits and safety procedures. Appointing him Secretary of the Interior in the first place was like putting the fox in charge of the hen house.
(2) Order his crony, the Attorney-General (who called America "a nation of cowards" in his Feb. '09 race-in-your-face speech), to issue arrest warrants for the executives of BP in addition to the CEO's of Transocean and Halliburton, and an international arrest and extradition warrant for the billionaire Chairman of BP, Carl-Henric Svanberg, sitting on his derriere in Sweden saying things to the press like "BP is big and important...The U.S. needs BP just as much as BP needs U.S. business." Since, realistically speaking, he cannot freeze all BP assets and nationalize all oil companies operating in the U.S., he could at least expropriate and comandeer every scientific and tecnhological honcho of all oil companies, who are doubtless praising Mammon that they don't work for BP, and perhaps, just perhaps, one of them knows of and is sitting on a solution which BP does not have, if the "top kill" fails.
(3) Demonstrate some humility and compassion.