This is a short list of basic things you can do today to protect your privacy. Obviously it's not exhaustive and there's a lot more to do if you're extra paranoid, but for a starter guide, this should give you a basic level of protection.
1. STOP USING GOOGLE AND FACEBOOK
They are collecting mountains of data on you, selling it to advertisers and loaning it to government agencies. Seriously, limit or stop all use of these services. Instead of using Google search I'd suggest checking out DuckDuckGo.com, a free software project that doesn't profile or track its users search queries.
2. USE FIREFOX
There's not much choice between browsers, but Firefox is the most open out of all the main gang. It is open source, which is a plus point, and it is not owned by a giant corp that's part of the PRISM surveillance program like Apple (Safari) and Google (Chrome).
3. GET SOME BROWSER EXTENSIONS
- Ghostery. Free but proprietary. Wikipedia describes it as enabling “its users to easily detect and control web bugs which are objects embedded in a web page, invisible to the user, that allow the collection of data on the user's browsing habits.” This means it stops the various servers owned by large corps such as Google, Facebook, Twitter from automatically tracking when you visit a website with their embedded code in it.
- HTTPS Everywhere. From Wikipedia “HTTPS Everywhere is a free web browser extension for Google Chrome, Mozilla Firefox and Opera, a collaboration by The Tor Project and the Electronic Frontier Foundation. Its purpose is to automatically make websites use the more secure HTTPS connection instead of HTTP.”
- AdBlock Plus. This is another free and open source extension similar to Ghostery, but aimed at automatically blocking ads. Apart from being useful to stop annoying intrusions, it blocks those ad servers from tracking you.
4. REMOVE YOUR INTERNAL WIFI CARD AND REPLACE IT WITH A REMOVABLE ONE
This simply allows you to have physical control over when you want to be connected to the Internet. If your system is compromised, even if it appears that your computer is not connected, it could still be sending packets. Being able to pull the plug at a moments notice is valuable.
5. INSTALL A SOFTWARE FIREWALL
This will simply allow you to decide what connects in and out of your system. There are a tonne out there, so have a look for yourself. One thing to note is if you torrent a firewall app, there's a chance it could compromise your entire system, so it's probably best to be legit here. You will be amazed at the amount of apps which constantly try to phone home to their servers.
6. DON'T INSTALL RANDOM SOFTWARE
This is linked to a point in the above section about torrenting software. I'm not going to tell you what to do in regards to torrenting, but be aware when you're downloading and installing random software there's a chance it's either completely backdoored or contains some level of spyware. If you don't NEED it, go without.
7. USE OFF-THE-RECORD (OTR) CHAT ENCRYPTION
See whether the chat apps that you use have OTR compatibility, and if so turn it on. This enables end to end encryption between you and whomever you're talking to, meaning that passive snooping cannot take place.
8. TURN OFF YOUR COMPUTER WHEN NOT IN USE
When you're not using your computer, turn it off completely (and remove that new external wifi card). Aside from being better for security (in terms of getting passwords from RAM), you can guarantee no apps will secretly be phoning home.
9. LEARN ABOUT PGP/GPG FOR EMAIL AND USE IT
PGP (pretty good privacy) for email allows you to send and receive encrypted emails. You need to generate your own public key signature and share it with your friends. The catch is that they need to do the same (which can be frustrating). Be aware that your email content is the only thing encrypted, and anyone looking in will still be able to see other meta data.
10. GET A PASSWORD MANAGER
Password managers are great for generating and storing long complicated passwords so you don't have to memorize them all. The idea is that you can generate a brand new password for every single service or account you use, compartmentalizing any risk, so if one of those services is breached, everything else you use isn't automatically too. Make sure that you have a strong, memorable master password.
11. ENCRYPT IMPORTANT FILES
If you're on a Mac or Linux use the guide I wrote a few days ago to encrypt important files on your system. If your system is ever lost, compromised or stolen it'll be more likely that your files will remain untouched. Same goes for sending important files over the Internet. Maybe think about sending them as encrypted files.
Also look into full disk encryption for your computer. There are plenty of tutorials online to suit your particular set up.
12. COVER YOUR WEBCAM
This used to be the reserve of hyper paranoid individuals, but the Snowden revelations (and others) have shown that there are many operations secretly recording peoples webcam feeds. Yes, even ordinary people like you with nothing to hide.
13. REMOVE YOUR LAPTOPS INTERNAL MICROPHONE
This may seem a little paranoid, but if you don't ever use it, you may as well get rid of it. There is still a chance that your microphone is being listened in on. It's another way of mitigating the data that can be collected on you. You can always plug in headphones with a built-in mic when you need one.
14. TRY BITMESSAGE
Bitmessage is the decentralized answer to email. Basically what it does is allow you to send and receive messages in nearly total privacy. All messages are automatically encrypted so you don't have to mess about like PGP, and also the way the messages are mixed and collected means that a lot of the meta data like who is communicating with who and at what time, location etc is very difficult to ascertain. The apps are free and open-source. Download from Bitmessage.org (Win/Mac/Linux) or Voluntary.net (Mac)
15. USE THE TOR BROWSER
If you are working on sensitive material, you might consider using the Tor browser bundle. It automatically obfuscates your IP address, and provides a decent level of protection. There are some theories that it may have been broken, but they haven't been proven (yet) so be aware.
16. USE A MULTIHOP VPN
A VPN or virtual private network encrypts your network data through a server (or servers) and makes web requests on your behalf. This means when you visit websites, your IP address will appear as wherever the VPN's server is making the request from. They're good for stopping automatic ISP snooping, but they are not a magic bullet. Remember you are placing your trust in the VPN service, and some may not deserve it.
BONUS POINTS. STOP USING YOUR PHONE
Seriously. This is not something most people would be willing to do but if you really care about your privacy you should ditch the phone (aka George Orwell's worst nightmare). Think about it, this thing tracks your location in realtime, your movement habits, it knows who you are in contact with, it knows the exact relationship with each person and what you say to them. It knows what apps you use, what you browse for, how you browse, what you buy, what you don't buy, what people in your life look like and their location (with photos and geo tagging). I mean for fuck sake that's insane. Phones are much less configurable than computers so you have even less control of your data.
If you're not willing to do that, then at least remove the battery from your phone (if you can), when you're not using it.