Was there any indication let's say 10-20 years prior to WWI that there would be a war or rising tension between European countries?
Here's some answers I've given previously on the subject
[The Balkan Wars] (https://www.reddit.com/r/AskHistorians/comments/32gnjo/1912_war_in_the_balkans/)
[Lead up to and outbreak of WWI] (http://www.reddit.com/r/AskHistorians/comments/35vtov/discuss_the_causes_of_world_war_i_what_were_the/)
[Balkan Nationalism and the Outbreak of WWI] (http://www.reddit.com/r/AskHistorians/comments/37n91p/to_what_extent_did_ethnic_and_nationalist/)
The 1890s saw the formation of the Triple Alliance (Germany, Austro-Hungary, Italy), the formation of the Franco-Russian and Franco-British Ententes, and the Anglo-German Naval Arms Race began.
The early 1900s saw the First and Second Moroccan Crises, the Bosnia Crisis, the First and Second Balkan Wars and the Scutari Crisis. It saw the beginning of a Land Arms Race in 1912, starting with Russia, then Germany and France.
There was growing tension. Germany's pointlessly aggressive stance in Morocco, combined with the naval arms race, alienated the British, and drew them closer to France, while events in the Balkans lead to increasing Austro-Russian antagonism.
However, considering the lengthy affairs these crises were, and the important issues at stake, few civilian and even political observers believed that an assassination in Sarajevo could possibly lead to war. The pace of events in the July Crisis was much greater than in previous crises, and so decision makers found themselves under greater pressure.
I always liked this quote from Otto Von Bismarck in 1888 "One day the great European War will come out of some damned foolish thing in the Balkans". 26 years later he's be proven exactly right.