I will not be bullied into giving up XP. For those of us who can’t or won’t make the change, what can we do to stay safe online?
Ari, you aren’t going to be completely safe online without Microsoft offering security support for the product. While XP is a stable operating system, it’s not a particularly secure one. XP machines were six times more likely to be infected with Malware and that was back when Microsoft was still offering security support. I would suggest switching to a newer version of Windows or perhaps running dual-boot with Ubuntu and keeping XP offline. 
Any advice on keeping XP more secure is a bit like advice on keeping your house safe without locking the door. So this is a like telling you how to put a chair against an unlocked door to keep out thieves. But there are a few things you can try:
Keep a third-party security software and malware program running. I would recommend using a paid subscription software, as opposed to a free version, as the paid versions will often allow for real-time protection and additional security. Do checks and updates every day. While these companies won’t be receiving new information from Microsoft, your security programs can still go after known threats. Some security programs say they will still actively try to detect new Windows XP threats, but without access to critical information about the program from Microsoft, they will not be able to permanently patch any of these threats. So like a cold, these bugs can come back again and again and again.
Make sure you have your firewall turned on . You’ll find it in your Control Panel.
Switch to Google Chrome or Firefox for your browser. Definitely do not use Internet Explorer 8. It’s old and creaky and insecure. Chrome says it will do its best to keep XP safe for an additional year. Make sure to change your default browser from IE .
Be very careful what types of e-mails you open and what sites you go to. Also, protect your friends and family and be very careful what you forward them or don’t forward them any files at all from your computer. Your computer could turn into Typhoid Mary. It may not look or feel sick, but it could pass bugs along.
Create a user account that does not have administrative privileges  and use that account. A limited account will not be able to install any programs and that can offer protection from some types of threats.
These tips will keep your system somewhat safer, but not safe. Every time Microsoft issues security patches for Windows 7, hackers can use that update to try to find similar flaws in Windows XP that won’t be patched. XP computers are especially vulnerable. Good luck.