Match chart to question
Lines for trends over time, bars for comparing categories, scatter for relationships, histograms for distribution shape, heatmaps for dense matrices. Pie charts work only for a couple of slices; humans compare angles poorly.
Honest encoding
Start bar axes at zero, avoid dual axes that manufacture correlation, sort categories meaningfully, and label directly instead of forcing legend lookups. Choose colourblind-safe palettes and reserve saturated colour for the point you are making.
Dashboards and narrative
A dashboard answers a recurring question and should fit one screen with the headline metric first, comparison second and detail on demand. For a one-off analysis, lead with the conclusion, show the evidence, and state the uncertainty and what would change your mind.