Secure wireless networks - Leaving wireless network connections unsecured at best means neighbours can gain free access to the internet and at works leaves your home network exposed to hackers.
Microsoft provide a useful guide to setting up and securing a network:
However you can take precautions to protect yourself from attack. Installing good virus software is critical these days, this will block any unwanted attacks from malicious sites or hacker attempts.
Another great way to keep safe is to protect yourself when checking your email box. Never open any mail your suspicious about and be very careful when opening attachments.
With the increase in social networking sites and instant messaging services has also come the increase in people looking for ways to gain access to your computer. Harmless looking friend requests or games, can often hide malicious code that can access your computer and cause havoc.
The internet is a fun place to be and relax. By taking the measures outlined above, you can make sure that, you surf, chat and tweet in safety.