Some of the controls in Project Zomboid are intuitive, whereas other ones are not what you would automatically assume.
WASD: Movement
Left Ctrl: Can be used to attack when a weapon is equipped in your primary slot.
Left Shift: Sprint, increases your speed. Your speed will decrease as you become tired of moving at a quicker pace. Shift clicking on a window with curtains or sheets on it will open or close the curtains/sheets.
E: Interact with doors/windows/etc
1: Equip/Unequip Handweapon
2: Equip/Unequip Firearm
3: Equip/Unequip Stab Weapon
F: Equip/Turn On/Off Light Source
Right Mouse Button: Is used to move if you don’t want to move using the WASD. Simply hold down the right mouse button and your character will move towards the mouse pointer. The farther away the pointer is from your character the faster he will attempt to move. The RMB is also used in combination with the LMB to drag objects around. If you have the right mouse button down and you left click your character will make an attack in that direction.
G: Changes the graphic level.
M: Turns the music on or off.
Q: Shout (can be used for attracting the attention of the zombies or npcs)
I: Expand/Collapse Inventory
C: Toggle Skill Panel
J: Toggle Info Panel
H: Toggle Health Panel
P: Pause
F3: Normal Speed
F4: Fast Forward x1
F5: Fast Forward x2
F6: Fast Forward x3
=: Zoom In
-: Zoom Out