(1) If your RPi is difficult to access physically, then making backup on a PC or NAS over network is the practical way. In this case use the method shown in first post of thread linked above by @keithma. That thread uses raspiBackup.
(2) If your RPi is physically accessable, you can shut it down, slipout microSD card, slip in a USB card reader, plug card reader into Windows PC and make a backup copy using Win32DiskImager.
(3) If your RPi is physically accessable, but you want to make a backup without shutting it down, you can do it by slipingin a spare microSD card in a USB card reader and plugging it into RPi. The backup copy will be made on this apare microSD card while RPi is still booted. For details, please see this post