How would you prepare 1000.0ml of 0.600M NaOH solution starting from concentration of 1.000M

I would use the dilution formula.

c1v1 = c2v2
1M x V1 = 0.600 x 1000 mL
Solve for V1 in mL; place that # mL in a 1 L volumetric flask, make to the mark, shake thoroughly.