Things like YouTube videos, or "Android enthusiast" sites tend to provide outdated, oversimplified, or in the worst (yet surprisingly common) case, completely wrong advice on how to root your device.
If you do not know enough to separate the bad advice from the good, stick to commonly trusted sites like XDA-Developers.
If any article, comment, or video tells you you can root your device without the need of a computer, ignore their advice.
Either they're stuck back in Android 4, or they are asking you to install malicious programs on your device. In either case you most likely won't get what you're looking for.
While the common concepts are the same, there is no universal way to root every single device. If any article, video, etc. promises you a way to root every device universally, ignore their advice!
If anyone is asking for payment in exchange for rooting your device, ignore them
You will most likely get scammed. Even if you don't, rooting is not something particularly hard, it only requires patience, the ability to follow guides without skipping steps, and the ability to find the truth between a lot of bullshit.
You cannot root safely without unlocking your bootloader. If you can't unlock your bootloader, consider giving up.
Unfortunately, not every Android device is rootable. If you happen to be looking for a new device, consider taking into account an active developer community, bootloader unlocking, and custom ROM support.
Huawei should be highlighted in that, despite advertising heavily on places like XDA, they do not allow for bootloader unlocking. There might be certain workarounds with brute-force cracking unlock codes, but expect to not be able to do that.
Cheap, no-name devices, or devices from "local" brands that don't exist (with the same branding) outside your country, might not be rootable! The more popular your device is (globally!), there more chance you have of being able to root it.
Certain apps will break after you root your device. Check if you
use an app that breaks after rooting. The main thing to look for is if
the app uses SafetyNet or something similar.
You can trick them into working, but that is a big cat and mouse game, and you should expect to not be able to do that.
Some known examples are streaming services, banking applications, and possibly games (as an anti-cheat measure).
Samsung specifically should be highlighted, in that they will break various features after rooting. This might range from things you can ignore, like Samsung Pay (which, as far as I'm aware, breaks permanently, due to KNOX), to important things like the camera (on certain foldable models).
To root most Android devices, you'll generally need ADB/platform-tools, a custom recovery, and Magisk. Make sure you trust the sources you download these tools from.
Some devices might require extra tooling, like Samsung's Odin, or Xiaomi's unlocker tool. Be careful about the sources of them as well. Don't accidentally get a virus or anything!
For security reasons, unlocking your bootloader will permanently wipe your data. Don't forget to back everything up!
Just saying "I have a Samsung" isn't enough. Give as much information as you have. Exact model numbers, the carrier you got your device from (if any, and they do matter), etc.
Even saying "I have a Samsung XYZ on Android 10" might not be enough. Samsung specifically uses different SoC's on their phones depending on the region. And some are not rootable.
If your device has an "internal" model number that looks like a random series of numbers and letters (SM-G973F, A2017G, XT1962-05, etc.), do share that along as well!
If you are willing to part with any vendor-specific features your device might have, consider installing an AOSP-based custom ROM, if your device has any.
Custom ROMs generally contain less "bloat" than OEMs (preinstalled Facebook, anyone?), allow for more built-in customizations, cooperate better with 3rd-party modifications, get more updates, and (personal opinion) look cleaner than any OEM skin.
As Android gets updated, old tools and guides will not work. Consider looking for newer approaches on doing stuff.
For example, any guide that tells you to mount your
/system partition as read-write is obsolete. Modern Android
versions will most likely won't allow that. Instead, take advantage of
Magisk's module system.
If a modification needs SELinux disabled, or if a custom ROM isn't stable enough to work with SELinux enabled, consider not using them.
SELinux is a very important piece of the Android security system. Disabling it can introduce very serious vulnerabilities. Don't take it from me, take it from Magisk's creator.
Just about all of them are weird placebo tools that don't do anything significant except look nice.