How did the Spanish succeed in fulfilling their goals of conquest and colonization in the Caribbean and California? How did they fail?

Following Columbus's initial voyage to the New World in 1492, Spain began to colonize the Caribbean, Latin America, and parts of North America. Their goal was initially to extract as much gold as possible, and they did so, constructing mines in Latin America that produced much of the world's gold supply. At that time, gold was used as the international currency, and Spain gained a great advantage in trade with other European countries. Eventually, however, wars with other European nations such as the English and Dutch left Spain in debt. In addition, colonists in Spanish territories began trading with other European powers, such as the English and Dutch, leading to Spain's decline as a world economic and imperial power.
In addition, Spain sought to found plantation systems called encomiendas through which conquistadores enslaved Native Americans in return for Christianizing them. The planting of sugarcane, a very valuable commodity, led to the eventual use of slaves imported from Africa. The enslavement of native people and Africans was brutal, and this brutality was an unfortunate consequence of Spanish colonization, as was the death of millions of Native Americans from Spanish violence and from the diseases the Spanish brought from Europe (to which the natives were not immune). Intermarriage among Spanish people, Native Americans, and slaves produced the mestizo culture, a rich culture that eventually sought independence from Spain. By 1824, most of the Spanish colonies (save a few in the Caribbean, such as Cuba and Puerto Rico) had fought and won wars of independence against Spain. In addition, California, in which Spain established missions along the coast, became part of Mexico. Therefore, the Spanish conquest did not last in most of its conquered lands.