My field is International Relations rather than History, but I hope I can help you out. I would also encourage you to ask this in /r/Ask_Politics for more info, as Bismarck is studied extensively by anyone studying politics.

Bismarck was certainly a great politician, but you cannot place every single bit of German success squarely onto his shoulders. He created the final product, but he also had some great tools at his disposal. Industrialization had finally begun to take off in the German speaking territories in the 1840's to 1850's, especially in his own Prussia. This gave him a strong economy. He also had the best military on the continent by far at his disposal. Albrecht von Roon successfully reformed and expanded the Prussian army. Voltaire is thought to have said "Most states possess an Army, but the Prussian Army possess a state" which showcases the warrior culture of Prussia. Drawing on the support of the Junkers, who were the aristocratic warrior elite, and on the legacies of Frederick the Great, Roon was able to turn a good military into one that was probably the best in the world. This army was put into the hands of Helmuth von Moltke who was a brilliant strategist and reformer in his own right.

Bismarck's brilliance came in his use of these tools to form a Prussian dominated German state. To do this, he basically had to do three things:

1. Begin to draw the German people together, awakening pan-German nationalism. He did this in the Second Schleswig War, by creating a conflict with Denmark. It's more complicated than I would really want to get into here, but essentially Prussia and Austria jointly declared war on Denmark over a minor territorial dispute, which demonstrated Prussian strength and riled up the population to support unification.

2. His second step was to exclude Austria from the proposed German state. He did this by using disputes with Austria over annexed Danish territory. In the Austro-Prussian war Prussia's new and improved army was led to a quick victory by Helmuth von Moltke. This is where Bismarck had a really good idea. Rather than push their luck, continue the war, and hope to gain more territory, Bismarck successfully pushed for a limited war. Prussia annexed Austrian Holstein and some Austrian allies, but more importantly, Austria agreed not to interfere in German affairs. This lead to the eventual creation of the North German Confederation.

3. Bismarck wanted to turn the strong but still loosely held together North German Confederation into a true empire. He also wanted to add the southern German kingdoms. He regarded war with France as a neccessary prelude to German unification. He basically manufactured a political crisis involving a Prussian prince claiming the Spanish throne. The claim was withdrawn, but Bismarck managed to goad Napoleon the Third into declaring war by essentially insulting his envoy. The French declaration of war branded them as the aggressors in the eyes of all the Germans, not just the Prussians. The Bavarians, plus other south Germans, were drawn in on the side of the Prussians. The Prussian victory (brought about by that excellent Army) cemented their position as the center of Germany. The German Reich was declared in the immediate aftermath of war, creating a new continental power.

After Unification, Bismarck continued to act intelligently. In World politics, a balance of power does not always lead to peace, nor does an imbalance lead to war. After unification, Germany was universally regarded as the premier continental power. Bismarck's strategy was to isolate the only power with which they had poor relations, France. He managed to keep France basically without allies using his policies. He kept the League of the Three Emperors between Austria-Hungary, Russia, and Germany active as long as possible, and when that fell apart he signed the Reinsurance Treaty which assured neutrality between Russia and Germany. He also avoided challenging British naval supremacy, a policy not continued by his successors. By not challenging Britain, they mostly maintained traditional British neutrality in continental affairs. But when what was clearly the strongest continental power began building a large fleet, the British lined up with France and Russia, setting up the alliance system that lead to World War 1. Bismarck knew that Germany's limited coastline and numerous choke points would make challenging Britain directly difficult. When the new Emperor ordered a build up anyway, it led directly to a realignment of Britain on the side of France.

Alright, that's my best simplified version of Bismarck's major accomplishments. There are a ton of other details, and I didn't even touch on his domestic policies, which were also pretty brilliant, but here are the basics.

EDIT: For something more in depth, read Bismarck: A Life by Johnathan Steinberg. I got it two years ago, and not only does it expain his tactics and though processes, it also goes into his personal relationships with other influential figures, including Roon and Wilhelm. It's a great read overall.

EDIT 2: Thanks to whoever gave me gold, and whoever submitted this to /r/bestof ! It's an honor, especially from a sub like this!

A famous quote of Bismarck's describes his approach pretty well: "A statesman cannot create anything himself. He must wait and listen until he hears the steps of God sounding through events; then leap up and grasp the hem of his garment." Meaning that he was very good at identifying and making the best of opportunities.

I would also recommend the most recent series of "Hardcore History" podcasts on WW1 and what precipitated it, called "Blueprint for Armageddon". There is a great breakdown of Bismarck's impact on Europe, and how weak leadership caused his systems to crumble.