Convert all values to decimals for easy comparison:

• $0.08 = 0.08$
• $0.6 = 0.60$
• $\frac{5}{8} = 0.625$

Ordering from least to greatest:

$0.08 < 0.6 < 0.625$

The correct order is $0.08,\; 0.6,\; \frac{5}{8}$.