I'm not an expert about that but i'll try to help you, but you can search in this forum about that.
Not only almoravids, also almohades were berber people. The main difference is the race. During arab domination arab people was a minority but they have the main positions. Arab were warriors but also bring to Spain many things, culture, medicine, agriculture, etc. They want to improve the living level, but almohades and almoravids not, they come from the desert and they were mainly warriors and not developed the kingdoms, they came because the muslim called them to fight againts christians and they took advantage of many internal conflicts in muslim Spain.
The main conflict was the land, there were a border war like in the US with the natives. During peace periodes the people without the king made some incursions in the territory of the other kingdom. There were some aspect very impostant, the most, obviously, the religion. In Spain the wars againts muslim were other crusades, not only in Holy land, and real crusades with the acll of the Pope and many foreigner soldiers.
The idiea of a war promoted by the kings is false, were the people. But there were also places and times with peace, the most well-known is Toledo with the translators School. The demographic pressure in Castile was high and they need more land. The land above Duero River didn't have many population, was a natural border and Christians take profit and settled them. Another point to the conflict was the taxes, fisrt were the Christian who had to pay to Muslim, and for example Almazor did many Razias againts Barcelona or Santiago. After was the opposite, the muslim Taifas kingdoms had to pay to Christian kingdoms, mainly Castile and Leon.
It's a very complex periode and very long, i cannot say many things so fast, and without many time, i hope you'll be successful in your work.