Empire-building comparison: Spain and Ottoman
To evaluate the process of building an empire, the peak of it must be known. According to my knowledge, the peak of Spain and the peak of Ottoman are very close.
For Spain, I would consider the peak as the time when it holds as much power as Portugal, due to the fact that the two empires both profited in the sea discovery period. So I would say the time around the publish of the Treaty of Tordesillas is the peak of Spain.
For Ottoman, I consider the time when Ottoman destroys the Constantinople as the peak, because I believe it could be a sign that the Ottoman empire finished expanding the lands and starts to work on the trades and social policies overland.
Considering the peak of both Spanish and Ottoman empire are in the same period(1450-1500), it would be easier to analyze the differences in the progress of building their empires.
Firstly, the strategy of oversea trading is very different, as to Spain, they are more focusing on taking over the lands and transforming them into colonies, so socially and culturally speaking, Spain has set up deep culture influences on its colonies. But Ottoman is different, due to the geographical difference, Ottoman was able to maintain both trades in the west(sea) and east(land). So according to the name “Sea Empire” people gave to Spain, I would say that Ottoman could be more of a Sea and Land Empire.
Secondly, for cultural differences, the religion of Spain empire is simple, and the church owns the absolute righteousness as the spiritual leader, but Ottoman is diverse, it provides multiple religions for the citizens.
The Millet system in Ottoman is an evidence for its development of diverse culture. It protects the rights of the non-Muslim community and offers citizen their equality. As for the non-Muslim population, government taxes and jobs is the price to pay. The relationship between to Muslims and non-Muslims were similar to the relationship between the center China and the other autonomous regions in China right now; China provides the jobs and schools for the young, it is efficient in easing the contradiction between religion and national class and also conducive to social and economic development.