You probably don’t realize it, but some of the simple things you do on the web everyday could be putting you and your computer at risk. In the case of online security, what you don’t know can hurt you.

Here are a few common online activities that could potentially make you vulnerable.

1. Using public Wi-Fi networks

We all do it, but that doesn’t mean it won’t get us into trouble. Using public Wi-Fi, especially in crowded places like coffee shops and airports, can open you and your computer up to a number of attacks.

“Public Wi-Fi is fraught with security problems. Commonly named networks, like AT&T or Starbucks Wi-Fi, are very easily spoofed to capture your logins,” says Seth Rosenblatt, managing editor of the security and privacy news site The Parallax. “Security on public Wi-Fi is generally low,so even if it is a legitimate network, it’s often easier to hack into than private Wi-Fi.”

In other words, when you think you’re connecting to “Free WiFi” at your hotel, you could actually be connecting to a fake network designed to capture your passwords and other information when you try to login. In cases where you need to use a public network consider using a Virtual Private Network (VPN), which will encrypt your data and give you the security of your own wireless network over a public connection, to keep your information safe.

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“Even if it’s a Wi-Fi network with a password in a coffee shop, you’re very vulnerable to being hacked on that network,” says Danvers Baillieu, chief operating officer of the VPN service Hide My Ass. “If you’re out and about and you’re not sure whether a Wi-Fi network is real or not, then it’s a good idea to connect to a VPN.”

2. Filling out online forms

While you certainly need to be careful with how you connect to the web so your information isn’t stolen, you need to be equally careful about what information you pass out to third parties.

“Obviously if you give information to a website, no technical solution is going to help you,” says Baillieu. “It’s really just a question of being alert when you’re online and not handing over your information to websites you don’t trust or [information] that isn’t necessary for the tasks that you’re trying to carry out.”

Many websites collect information about online activity and turn around and sell it without your permission. Before passing out things like your email address, physical address, or phone number make sure you know exactly what a site plans on doing with it. The same goes for logging into third-party sites using your Facebook account. Sure, that single login makes it easier to use a new service, but it can come back to bite you. For example, it’s easy to inadvertently grant a site permission to share content on your Facebook wall or with your friends.

Likewise, you might want to give out your phone number to a company you’re considering renting office space from. First, however, you should make sure the company won’t turn around and sell it to other brokers if the space you’re interested in gets rented out from under you.

Be sure you know what you’re agreeing to before you pass along personal information.

3. Using the same password

Passwords can be tough to remember, but it pays to have a different password for every service you use. Particularly when it comes to things like banking information and email, you want to make sure you’ve selected a secure, unique password that would be hard for others to figure out.

Why? Security breaches happen. Passwords can get stolen. Think about it like this: If your house key was stolen, you wouldn’t hand over the keys to your car and office as well, right? Having unique passwords ensures that even if someone is able to access one of your accounts, they won’t be able to get into anything else with the same credentials.

Consider using a service such as 1Password that will create and remember unique passwords for you. You should also enable two-step authentication on any services that support it. With two-step or two-factor authentication, when you login your phone will receive a text message with a unique code that you need to enter to access your account. Even if a hacker has your password, without that code he or she won’t be able to access your account.

4. Sharing ­photos on social media

From snapshots of puppies posted on Facebook, to pictures of epic turkey sandwich lunches blasted out on Twitter, most of us share photos online. What you may not realize, however, is that your phone might be geotagging these pictures, giving others the ability to pinpoint exactly where you were when you took them.

Related: Be Sure to Look Around the Office When Searching for Gaps in Your Data Security

While that might not be a huge deal when you’re posting a picture of a sandwich taken at a local cafe, things get a little trickier when you’re sharing a picture of a sandwich taken in your home, inadvertently passing out your home address in the process.

An easy solution to this problem is to turn off geotagging on your smartphone. If you’d like to keep the feature, when sharing a photo online be aware of where the photo was taken,and strip the location data off of an image that might have been taken at a sensitive spot.

5. Blindly accepting privacy policies

Accepting privacy policies on websites is a necessary evil if you want to use a number of services on the web. Yes, they’re long. Before you sign, however, make sure you actually read through the privacy policy and understand what, exactly, you’re agreeing to.

“There are several important areas to check up on,” says Rosenblatt, most importantly “how the company treats your data.” He recommends looking for features that allow you to opt out of sharing your data, as well as features that enable you to delete your data when you delete your account. It’s also important “to look for how the company treats your data, such as the company's policy for notifying you of changes to the privacy policy, and how they secure your data from threats,” he says. “If you have children who might use the site or service, such as Facebook, it's important to look up how the company treats data created by your child. It's also a good idea to familiarize yourself with the company's abuse policy, in case trolling or worse becomes an issue.”

Bottom line: Be smart, pay attention and be careful what you share when you’re online. You’ll be glad you did.

Related: Do You Really Need to Change Your Passwords Every Three Months?