How to model effectively using exact measurements? How to Measure and Scale 3D Models in Blender
set the real-world units in the scene tab
Properties ‣ Scene ‣ Units
while in edit mode, select the "Mesh Edit Mode Overlays" in the upper right (the square with the upper right corner solid). Check the box Edge length. This causes the lengths of the mesh currently selected to be displayed.
if you scale an object in object mode, type ctl-A, then select "scale" to apply the scale.
Show the grid
Viewport Overlays
Guides
Check floor, x, y, and z
Navigation
change viewpoint
gizmo in upper right corner
select top, sides, bottom
drag to move viewpoint
click and drag with middle mouse button
move origin
click hand icon in upper right, drag
shift/middle mouse button, drag
focus on specific object
select object, menu -> view -> frame select
select object, numberpad period key
zoom in out
magnifying glass
mouse scroll wheel
number pad plus and minus keys
grid button - switch between orthographic and perspective view