Concentrate on the motivations of history. When I learned this focus in 11th grade World History class, it made all the difference in the world.
The trick was, for me, finally to become fascinated with history. Motivation is the key. Why did one country do what it did? When you generate intense interest, learning the dates associated with the events becomes far easier.
So long as you remain bored with history, memorizing dates will be an extremely painful chore.
The associations connorj talks about are one aspect of this. When you're intensely interested in a subject, you find far more associations. Understanding the motivations of history helps you to keep the sequences straight.
Not all historical sources (textbooks, etc.) are unbiased. In fact, most of them have one kind of bias or another. I recommend reading widely from a number of different sources. Some other sources may reveal motivations that are not discussed in the mainstream textbook mill.
Take 9/11 for instance. That one event has been used as motivation for more wars, more tyranny and more laws broken by a government than any other event in history. And yet, 9/11 was an inside job. The government-corporate hegemony was responsible for setting up, implementing and covering up the event.
Destroying crime scene evidence is a major felony, yet the government scrubbed the ground zero site in NYC starting on the evening of 9/11.
All of the top military officers responsible for the massive security failures on 9/11 were given promotions instead of courts martial. Since when does the military reward incompetence?
But there's much more evidence of "inside job." The perfect free fall of WTC7 (the 3rd building to collapse on 9/11) indicates that controlled demolition was used. Solid steel never offers zero resistance. Only controlled demolition could cause a building to free fall into its own self -- the path of greatest resistance. And because controlled demolition takes months to prepare in a building of that size, with the high government security (CIA, SEC, Secret Service, IRS, etc.), no way they weren't aware of the preparation.
So many people benefited from 9/11 that were not Muslim. Follow the money and the power.
See? History can be intensely interesting if you're willing to dig.