Practicing alone
From QWiki
Everytime you run QuakeWorld, there's the option to play by yourself, practice movement or aim, alone or against bots.
Aim
Popular maps to play Deathmatchmode4 (most commonly known as dmm4) mode are Endif, povdmm4, end, end2, amphi, midair. On KTX servers, the recommended map settings are loaded when the map is loaded, so you can /ready
immediately.
Movement
versus Monsters
see Bloodfest.
Bots
Bots replace human players. You can spawn bots in compatible KTX servers. See more Playing with bots.