A: G-d is responsible for everything, including your ability to do the things you can do. He granted you resources and the capacity to exercise free will in utilizing them. Moreover, even the best laid and executed plans are dependent upon factors outside of human control, such as weather, health, chance occurrences, etc. So there is no contradiction between taking as full of a sense of responsibility as possible for accomplishing your goals while simultaneously recognizing that your success is ultimately dependent on the grace of Hashem.