France
  and Britain off against each other. Having relied on French arms to
  defend himself against the Italians in 1896, he made use of the
  British in 1902 when the French attempted to obtain excessive
  control over the Djibuti railway.

Source: Chapter 11 in A. Adu Boahen (ed), 'A General History of Africa, volume 7 (UNESCO)
Nonetheless, the treaties Ethiopia made were often very unfavourable and she lost some territory to Italy at various times up to 1896 (see below). In the early 20th century

treaties between European powers and Ethiopia were...laden with new
  and unequal caveats....The Tripartite Agreement of 1906 between
  Britain, France, and Italy attempted to divide the country into three
  spheres of economic interest without any input from Ethiopia’s leader,
 detained,
  placed in the custody of the French consul. In a similar vein, the
  Klobukowski Treaty of 1908 gave European residents in Ethiopia similar
  extraterritorial rights and fiscal privileges.

Source: Adejumobi

Military
Under the emperors Tewedos II, Yohannes IV and Menelek II, Ethiopia modernised and expanded her armed forces until they were the most formidable of any African ruler. 

Realizing he could control the country only by military means,
  Téwodros decided to reorganize his army. His experience with the
  Egyptians, wrote a British traveller, Henry Dufton, convinced him that
  the 'primitive mode of warfare' would have to be 'superseded'.

Unable to import significant quantities of modern arms due to hostile neighbours, Tewedos hired expert Europeans to manufacture cannons, mortars and shells in Ethiopia. Tewedos also reorganised