buy a home, build a DADU, sell both units after DADU complete, tax saving strategy?

[Yu Xiao]

If we purchases a home as an investment property, build a DADU, and sell the home and DADU (around 12 months after the purchase), what's the best strategy for tax saving?
My partner and I are both on the higher end of tax bracket, anything we could do to help reduce the tax bill from these transaction? 

Thanks.