What factors led to the decline of the Ottoman, Safavid and Mughal empires?
Invasion, economic destitution, and growing European power all played a role in the decline of the final three Muslim Empires. Apologies if my answer is too long... :)
The Ottoman Empire would grow so large, that the central government's hold on the villages and cities it conquered, would decrease. Local governments, as a result, take matters to their control, and this leads to heavy taxation, that leads to corruption. The Ottoman sultans would kill their own heirs in desperate measures to stay on the throne as long as possible, and indulged in drugs and luxuries that spoiled the quality of the empire.
The once powerful Ottoman military navy and army, would start to fall as well. With a major naval defeat at the Battle of Lepanto (Ottomans vs. Venice+Spain), the Ottomans would find themselves powerless against blocking European trading and military vessels.
The Ottomans would continue to survive until the 1900s, but will never be as powerful as they once were; they fought in World War 1 under the nickname " Sick Man of Europe "...
The Safavid Empire would face a faster decline than the Ottomans. Shah Abbas 1 would kill his sons, and blind alot of men, in a greedy attempt to stay on the throne. When Abbas 2 comes over to rule the Safavids, the empire was already declining, both bureaucratically and authoritatively.
The Safavids also experienced an invasion by Afghani tribes, who turned the Safavid empire into their battleground. Although a leader named Nadir Khan Afshar would come to rule the Safavids to restore order, it was too late...the Safavids were done for.
The Mughals were also fast in their decline, although traces of their empire continued to persist until the nineteenth century. The Mughals started to decline under Aurangzeb, the son of the famed Taj Mahal builder, Shah Jahan. Aurangzeb would grow his empire to great extents, but his religious intolerance and inability to keep regional governments in line, would leave the Mughals broken, and an easy prey for the incoming European powers.