Use the package manager to install software
Pacman does a much better job than you at keeping track of files. If you install things manually you will, sooner or later, forget what you did, where you installed to, install conflicting software, install to the wrong locations, etc.
From a stability standpoint you should try to avoid unsupported package and custom software, but if you really need such things making a package is better than manually compiling and installing.
Prefer open-source software
Wherever possible, choose open source drivers. Try to avoid proprietary drivers. Most of the time, open source drivers are more stable and reliable than proprietary drivers. Open source driver bugs are fixed more easily and quickly. While proprietary drivers can offer more features and capabilities, this can come at the cost of stability. To avoid this dilemma, choose hardware components known to have mature open source driver support with full features. Information about hardware with open source Linux drivers is available at linux-drivers.org.
Be careful with unofficial packages
Use precaution when using packages from the AUR or an unofficial user repository. Most are supplied by regular users and thus may not have the same standards as those in the official repositories. Be careful with AUR helpers which highly simplify installation of AUR packages. Always check PKGBUILDs for sanity and signs of mistake or malicious code before building and/or installing the package.
To simplify maintenance, limit the amount of unofficial packages used. Make periodic checks on which are in actual use, and remove (or replace with their official counterparts) any others. See pacman/Tips and tricks#Maintenance for useful commands.
Upgrading the system
Regularly upgrade the system
It is recommended to perform full system upgrades regularly, to enjoy both the latest bug fixes and security updates, and also to avoid having to deal with too many package upgrades that require manual intervention at once.
Users must recognize that due to the nature of Arch's rolling release approach, an update may have unforeseen consequences. This means that instead of updating immediately as soon as updates are available, users should update during free time and be prepared to deal with any problems that may arise. It is not wise to update if, for example, one is about to deliver an important presentation.
If the system has packages from the AUR, carefully upgrade all of them.
Read before upgrading the system
Before upgrading Arch, always read the latest Arch News to find out if there are any major software or configuration changes with the latest packages. Before upgrading fundamental software (such as the kernel, xorg, systemd, or ) to a new version, look over the appropriate forum to see if there have been any reported problems.
Act on alerts during an upgrade
When upgrading the system, be sure to pay attention to the alert notices provided by pacman. If any additional actions are required by the user, be sure to take care of them right away. If a pacman alert is confusing, search the forums and the recent news posts for more detailed instructions.
Deal promptly with new configuration files
When pacman is invoked
.pacorig files can be created. Pacman provides notice when this happens and users must deal with these files promptly. Users are referred to the Pacnew and Pacsave files wiki page for detailed instructions.
Also, think about other configuration files you may have copied or created. If a package had an example configuration that you copied to your home directory, check to see if a new one has been created.