This short bit from Ableton's Learn Live series covers six essential Session View shortcuts for navigating and manipulating clips without reaching for the mouse. Arrow keys move between clips, Shift+arrows extends the selection, and Enter launches whatever is selected.
Ctrl/Cmd+A selects every clip in the set at once, Ctrl/Cmd+D duplicates the current selection in place, and holding Ctrl on PC (or Alt on Mac) while dragging copies a clip into any empty slot. Small habits, but they add up fast when you're moving through a live arrangement or building out a session.