This is a list of changes I usually make after a fresh OpenSuse installation.
Changes in System
Install Oracle Java. Instructions are here.
Changes in KDE
Add Windows style keyboard shortcut Meta + D to Show Desktop
Global Keyboard Shortcuts -> Kwin -> Show Desktop
Lock screen with Meta + L
Global Keyboard Shortcuts -> The KDE Session Manager -> Lock Session
Disable Background Services
Configure Desktop – > Desktop Search -> Uncheck Enable Nepomuk Semantic Desktop
Software Management -> Uninstall Akonadi
Akonadi and Nemopuk consume a lot of resources and result in significant lags in the user interface even in top machines. I never experienced applications opening slowly after disabling these two services. Credit to here.