Joshua already had the preparation for ministry of having been Moses’ servant since his youth (Numbers 11:28). He had faith to be one of the two spies who believed that Yahweh was capable of fulfilling His declaration that He would give the descendants of Jacob the land that had belonged to the descendants of Canaan (Numbers 14:8).
In Exodus 33:7-11, what may have been the description of his real preparation for leadership says that Moses would knock off work and head into the camp, but Joshua would stay inside the tent of meeting, where Yahweh was manifesting and talking to Moses as a man talks face to face with another man. Joshua would just stay there.
Just spending time away from everyone else can empower you to greatness if you spend it in the Spirit of Yahweh. You don’t have to be speaking or hearing anything to be changed by His presence.
On the days with the wondrous place is filled with the whisper of His voice, you will be changed and led.
Find the place of meeting that He is drawing you to. Hide from all else and all others. Spend time there. Be changed and be led.