Decimal to percent:
Multiply the decimal by $100$.
$\left(0.34\right)\left(100\right)=34\%$

Fraction to percent:
Set up an equivalent fraction using $100$ as the denominator. The numerator is the percent. $\frac{4}{5}=\frac{80}{100}=80\%$

Decimal to fraction: 
Use the digits as the numerator. Use the decimal place value as the denominator. Simplify as needed. 
$0.48=\frac{48}{100}=\frac{12}{25}$

Percent to decimal: 
Divide the percent by $100$. $78.6\%=78.6\div100=0.786$

Percent to Fraction: 
Use $100$ as the denominator. Use the digits in the percent as the numerator. Simplify as needed. 
$22\%=\frac{22}{100}=\frac{11}{50}$

Fraction to decimal: 
Divide the numerator by the denominator. 
$\frac{3}{8}=3\div8=0.375$