Diagrams have THICKER lightweights than drawings. Aim to be simple, clear and bold. Use a very limited range of line weights. 0.7mm or 2pt - Outline thicknesses 0.2mm or 0.5pt - Typical thicknesses 0.05mm or 0.15pt - Extra information/ Detail thicknesses Use bold bright colours to highlight something. Use colour decisively. Be aware: smaller diagrams might need smaller line-weights. Refer to works by BIG, REX and OMA for good examples of diagrams.