How to maintain anonymity on the Internet
Content
Levels of anonymity
Rules of online behavior
Methods of obtaining information about you and how to resist them
In conclusion
Anonymity is important for all Internet users. Neglect can lead to personal data and photos falling into the hands of intruders, to the loss of money from electronic wallets and bank cards. Therefore, everyone should know the basic rules of anonymity.

Levels of anonymity
Anonymity can be different. It's one thing when you hide your data from an interlocutor in an online chat, and quite another if you are trying to "hide" from the state. Tor, VPN and other methods do not provide complete anonymity if you use them from a regular computer, via the home Internet or your smartphone. It's like if you called the police, introduced yourself by someone else's name and reported a bomb in a changed voice — but called from your personal phone. 

This does not mean that complete anonymity is impossible. It is possible, but it is a troublesome, expensive and requires special knowledge. A guide to complete anonymity posted on the website anonimousplanet.org , contains 500 Kbytes of a single text (excluding graphics) and requires several weeks only to read and comprehend. But in fact, few people need such anonymity. As long as you are not doing anything illegal on the Internet, you can do with partial protection — from the unwanted interest of other network users.

Rules of online behavior
The first thing that anonymity depends on is user behavior. Virtual machines and encrypted traffic connected via a hand-bought SIM card will not help if you give an online interlocutor a link to your social network page.

Therefore, the first step in achieving anonymity is to follow the rules of network security:
use complex logins and passwords;
do not tell strangers and do not leave your personal phone number, email address and links to a social network page on unverified sites;
if you need to give a phone number and email address to strangers for work, get a work number and mail;
do not tell strangers and do not leave your full name and mailing address on unverified sites;
do not send confidential data by mail or messages;
do not click on links in emails from strangers and from unfamiliar addresses, if a friend sent a letter with a link, first make sure that it was not hacked;
do not install questionable applications, especially "hacker" ones — 99% of these hack only one computer — yours;
do not access unverified sites using social networks — the "Log in via" button allows the site owner to get almost all information about you from the social network.
Methods of obtaining information about you and how to resist them
IP address
If you access the network from your home computer, your IP address can be uniquely mapped to you. Moreover, even after a long time, providers are required to store information about users' access to the network for 3 years. Your IP address becomes known to every site you visit. So it's not that difficult for an attacker to find out your IP address. Another thing is that it will give him little so far — only your place of residence with accuracy to the city. But you should not calm down — the IP address can be used to attack your computer in order to penetrate your system and gain access to information on the disk. Therefore, the security guidelines recommend changing the IP address when logging on to the network. How to do it?

Anonymous proxies (anonymizers). A proxy is a web server that receives all requests from you to the network, and then sends them to the recipient on its behalf, that is, substituting its IP. Regular proxies do not hide the initial IP address, passing it as service information. Anonymous proxies will not transmit your IP address further, pretending that they sent the request themselves.

There are a large number of anonymous proxies, both paid and free. The free ones often work with failures, are slow and can add their own ads to the pages. In addition, they do not provide any guarantee of confidentiality and may well belong to the attackers themselves. Paid ones are more reliable and faster, but again, it is impossible to guarantee that the history of your requests will not become known to someone else (as well as their content).
VPN. This is an analogue of a proxy server, only it also encrypts the transmitted data. When using a VPN, even your ISP will not know which sites you have visited and for what purpose. But the company that owns the VPN service knows this. All of them, of course, promise that they will not give this information to anyone, but history suggests otherwise. It is not uncommon for VPN owners to transfer information about users to law enforcement agencies. You can read more about VPN and its configuration on the router here.

Tor. How Tor works is written in this article. In short, this is a free VPN analog, only much slower. And there is also a point in it that knows "everything" about you — the output node. This feature of Tor is known to law enforcement agencies, so in many countries they themselves keep the output nodes of Tor. 
Unencrypted traffic
Over a standard http connection, all information is transmitted in a "pure" form. If you go to any site over the http protocol and enter your bank card data there, this number will be "seen" by all intermediate nodes through which you connected to the destination site, and there may be a couple dozen of them. 

Look at the browser's address bar: if there is no closed lock icon or the address starts with http://, then all your transmitted information is not protected in any way. 

Use only https when working on the network and be suspicious of sites that cannot provide an encrypted connection.

When using https, intermediate nodes cannot "read" your traffic. But they "see" which sites you visit, and — by the parameters passed in the address bar — they can guess what you are doing on them. VPNs and Tor provide additional encryption, hiding this information as well.

Mail 
The transmission of information by e-mail has its own vulnerabilities. Firstly, not all mail servers still use traffic encryption, and emails are transmitted in a "clean" form. Secondly, emails are also stored unencrypted on the mail server, and any server administrator can access them. Thirdly, companies that own mail servers are required to provide access to stored information to law enforcement agencies. 

Of course, you can negotiate with the recipient about the encryption method and password, and then encrypt all messages yourself and send them as an attachment. But this is inconvenient, especially if there are many recipients. 

Protonmail is a secure mail server located in Switzerland. Emails on the Protonmail server are stored in encrypted form, and only the owner of the email password, which is unknown to the service itself, can decrypt them. 

The transfer of emails between Protonmail subscribers is also carried out in encrypted form. So, by creating an account on Protonmail, you can be sure that the information you send is secure. Almost sure. Now, every time Protonmail connects, it sends executable code to the user's computer, which encrypts emails with a user password. The password itself is not transmitted to the Protonmail server. But there is no guarantee that one day the server will not send an executable code that will still give the password to someone who convincingly asks the owner of Protonmail about it.  

Wi-Fi
A wireless network is significantly more vulnerable than a wired Internet connection. To listen to a wired network, an attacker must have special equipment and access to the cable. And with Wi-Fi, everything is much simpler — you just need to be in its range, and all the data transmitted over the network can be "caught" on a simple smartphone with special software. So when working in a wireless network, special attention should be paid to security. You can read about all this in this article.
Cookies
Yes, yes, those are the "cookies" that many sites warn about when they log in. How are they dangerous? The fact that they store information that you entered on certain sites and that can get to intruders. 

And through the cookies for you to "follow" network aggregators like Google, Yandex, etc. Almost every site in the network has a metric of one or another aggregator, and when you log on to this website Google (or Bing) updates the data in its database about you. That you went to such and such a site, spent so much time there, were particularly interested in those pages and bought something. If this bothers you, use secure browsers and set up cookie deletion for all sites except trusted ones.

Trojans
If you store valuable information on your computer and hackers find out about it, they may try to hack your computer "from the inside" using a Trojan program. 

For example, on a website dedicated to cryptocurrency, you mentioned that you have a couple of bitcoins. Do not doubt that immediately after that you will find yourself under the scrutiny of hackers. "Somali Letters" is a kindergarten compared to the activities of professionals from the world of digital crime, who perfectly represent the power of social engineering. If a couple of weeks after that incident, on a completely different site, you suddenly meet an interesting and sweet person with whom you will establish a warm relationship, then one day you will not open the document sent to them? An antivirus will protect you from common Trojans, but what if the Trojan was written specifically for you? And now the seed phrase of your electronic wallet is leaking to the attacker. 

But is it really necessary to suspect everything and everyone? It won't take long to become paranoid. 

It's not necessary at all. There are several ways to prevent important data from leaking from your computer:

Firewall (firewall). The "fire wall" prevents applications from connecting to unknown nodes.