Is philosophy considered more important than other branches of knowledge, such as natural sciences or humanities/social studies/arts, because it teaches us how to use our knowledge effectively?

The answer should depend upon how you want to look at things and what sort of answer do you require, because if you want a deep philosophical question answered then philosophy is the most important branch of knowledge.

But if a scientist were to answer the same question he would say that natural sciences are more important because through empiricism or philosophical naturalism we have been able to develop this modern world that we see, on the other hand an artist would argue otherwise and bring the argument towards human aspect of our living and the entertainment side of our lives being the most important thing.

The actual answer to your question is that all of these fields of knowledge interplay with each other to help us know about our human existence and the world around us. To say that one is intrinsically better than the other would be an overstatement and clearly show bias. I personally think that each Field in its own way help us reach the truth.