@exculsively: brother if you want to understand (not cram) us history then you must read books...Regarding strategy you must try to cover maximum topics of us history...please DONOT solely rely on notes...try to read book's to have a grasp on the topic then you can cram from notes....you don't have to read whole of majumdar's books...following are some topics in my mind which you should do...
1.exploration and colonization.
2.war of independence.
3.federalist regime, federalsists vs antifederalists
4.Constitution of us, articles of confederation
5.jefferson , jackson, madison
6.slavery issues,compromises and civil war, abraham lincoln
7.Mexican war, west ward expansion, manifest destiny
8.spainish american war, us imperialism
9.progressivism
10.great depression.
11.ww1, ww2, FDR, truman , woodrow wilson and his 14 points, kennedy, johnson and vietnam, nixon ,
12. cold war, us economy boom after ww2, bush doctorine, obama doctorine, us withdrawl post 2014 from afghanistan, us economy and capitalism, new world order after fall of berlin wall
13.civil rights, women rights or more broadly the 60's era...
14.besides these if you have time then you may also read:railroads, urbanization reconstruction after civil war...
15.for questions from current affairs read newspaper regularly
you must also prepare a number of short notes as well like watergate, marshall plan, u2 crisis, cuban missile crisis etc you can have a look at the past papers to have an idea of what type of short questions are being asked...
for high scores try to include critical analysis before giving conclusion..critical analysis should discuss impacts of the event on future e.g you might include the impact of fall of berlin wall by stating that the us became world power or if you have watergate scandal you might include in your analysis that before the scandal the public polls showed above 50% americans had trust on politicians however it plummeted below 40 percent after this scandal...