Hi Shanthi,
You have beautiful eyes

.
Dark circles and puffiness are a sign of stress, vitamin / iron deficiency and no proper sleep.
Some recommendations -
Sleep properly for 8 hours every night, go early to bed and wake up early, late night can cause puffiness
If your job involves staring at computer for long hours, try to take some breaks in between.
When you come back home in the evening, put two cucumber slices over your eyes for 10 minutes to cool them
Have lots of water and eat leafy vegetables and carrots often.
Have a multivitamin and iron tablet often (consult your doctor for recommended dose)
Use an under eye cream at night - any good brand like Garnier, Shahnaz Hussain, Loreal or Lotus Herbals
Hope this helps and don't worry much about these things. Your inner confidence should radiate through your eyes and shine over all these minor blemishes all through your life.
All the best!