1. check the company name should be there there.        
2.check whether  off button is working or not. 
3.check whether the fan runs accoring the numbers like i, 
ii, iii ..
4. check the fan should have three wings.
5. check the fan should rotate clockwise direction.
6. check the company should give warranty card to the fan.
7. check the security of the fan, whether if we on the      
switch the fan should not fall down.  
8. check the fan should not make sound.