If you are just starting out, I would suggest heading over to Copyblogger and reading as much as you can. I think you will find this forum very useful in answering any specific questions you may have, but it is incumbent upon you to take an active role in the learning process. Copywriting is a multifaceted and nuanced trade. It is much too involved to explain in a few forum posts. Luckily, there is a wealth of information, freely available to you on the internet. I would encourage you to seek it out and then bring your questions back here. You will be amazed at how fast you catch up to speed.
hi mousumi, its very detailed just to give a quick response. i have written a quick article on killer copy writing you can view the link here. www.ccuk-ltd.com other than that you can pick up bits by reading and studying and following certain ways that writers work. it will take some time to learn. Kind Regards Stephen Doyle www.ccuk-ltd.com Killer Copy Writing Super Human Sales Training Direct Marketing
that's not something that is going to be answered in a forum post. Do a search on Google or Wikipedia and I am sure you will find the answers to your questions.
Now if your talking about copywriting for sales pages... I can't believe _nobody_ has mentioned Michel Fortin's Blog http://www.michelfortin.com/ On the subject of copywriting I also happen to read: James Brausch http://www.jamesbrausch.com/ Eric Graham http://www.conversiondoctor.com/conversion-blog/ Stephen Dean http://www.stephensblog.com/ Those sites alone should give you a good start... So go soak up as much free info as possible