How do you smooth out and shift money between personal and corporate C to prevent double taxation?

We have a fiscal year end in June 31 for the C

making the C corp 0 out will only hurt my personal taxes
so what do I do? BUy more stuff for the business??

How can a C Corp retain money in it without passing the profit off as dividends. Is there a specific amount the C corp can hold in profits for working capitol without distributing dividends?