If you feel that the site is asking for too much of personal information, just quit the transaction and leave the site. Don’t visit the site that fills your screen with pop-ups.
Be careful while shopping on mobile phones.
Most phones are not equipped with the anti-virus software. It is easy for criminals to get malware on your mobile phone. This will help them stealing of information from you. The shortened URLs are also risky. Theft of mobile phone is also risky. Make sure your phone is password protected.
Don't use public Wi-Fi to shop online. Most Wi-Fi hotspots don't encrypt your data. Any hacker nearby can just pluck your identity out of the air if he has the right software.
Check your credit card statement frequently. Use a virtual credit card number. Change your passwords regularly.
Look for https in the URL rather than http.
Don't click on links in emails. Instead, type out the address in your browser to make sure you're going to the site you think you're visiting.
Update your browser. Each new version of Internet browser gets a boost in security.