Peter was both pragmatic and reform minded, believing that Russia needed to become a Western power and that he needed autocratic power in order to take care of his subjects and work for the benefit of Russia. In 1697, he became the first tsar to leave Russia in over 100 years, traveling in secret (which did not really work because, at 6'8", he was quite easy to spot) to Western Europe on his Grand Embassy in order to secure alliances against the Ottomans and learn about Western science and technology (especially English and Dutch shipbuilding). It was after this trip that he launched his major reforms. While in London, he also had this portrait painted for King William III of England. 

Peter was especially eager to borrow European technology in order to create the army and navy he needed to make Russia a great power, and he implemented reforms to put Russia on an early path to industrialization, with Russia exporting more iron than any other country. Manufacturers and artisans were exempt from taxes, and industrial activities, especially mining, were protected from interference by local authorities. In 1721, Peter also passed a decree allowing factory owners to buy serfs, something previously reserved for nobles. Unlike in other parts of Europe, serfdom became further entrenched in Russian society, and owners had essentially total control over the lives of their serfs. The government itself owned millions of serfs, using them for building projects (such as the building of the city of St. Petersburg) and for work in factories or on agricultural lands.

To pay for his expanded military and many building projects, Peter instituted a poll tax (a tax on each individual, regardless of income). He modernized the Russian calendar and alphabet, established the first Russian newspaper, opened secular schools, and extended more control over the Orthodox Church. In 1714, he introduced compulsory education for all 10-15 year old children of the nobility, government clerks, and lesser-ranked officials so they could learn basic arithmetic, trigonometry and geometry. 

In one of his more controversial reforms (to the boyars, anyway), he instituted a tax on beards: any boyar who wanted to keep his beard had to pay 100 rubles per year). Military and government officials had to cut their hair and adopt western style dress as part of this efforts to make Russians look and act more like Western Europeans. 

To impose the rule of the central government more effectively throughout the land, Peter divided Russia into provinces overseen by bureaucrats. Distrusting the boyars (nobles), Peter dissolved the typical Boyar Duma (council of nobles) and instead hand-picked a Senate to supervise all judicial, financial and administrative affairs. Without his signature no Senate decision could go into effect; the Senate became one of the most important institutions of Imperial Russia. He used the Table of Ranks to create a "social elevator" for hardworking military and government officials and reduce corruption or unqualified appointments.

Peter's military reforms included employing both Russians and Europeans as officers and adopting western technology and training. He required all high nobles to serve in the military, and he also recruited peasants and ordinary citizens to build a standing army of 210,000 men and the first navy Russian navy, allowing him to acquire territory in Estonia, Latvia and Finland. Through several wars with Turkey in the south, he also secured access to the Black Sea. After conquering land from Sweden, he built the capital city of St. Petersburg (build largely by serf labor), building the splendid Winter Palace and providing Russia with a large trade port serving as a “window to the West.” 

Peter could be ruthless as well. After finding that his own son, Alexei, had plotted against him, he had him tortured so severely that he died. At times he faced much opposition to his reform policies at home but brutally suppressed rebellions against his authority, including by the Streltsy (infantry), who mutinied while he was traveleing in Europe. Peter brutally suppressed the rebellion and disbanded the Streltsy. His building projects, including the fabulous Peterhof Palace, required the labor of thousands of serfs, many of whom suffered miserable conditions. Both a reformer and a brutal autocrat, Peter succeeded in transforming Russia into a military power and an integral part of European diplomacy by the time of his death in 1725.