Begin with the legend
Map symbols are not universal. Read the legend to learn what line styles, colors, and units mean on that specific product. Check whether the map describes an observation, an analysis, or a forecast.
Pressure lines
Isobars connect places with equal atmospheric pressure. Where they are closer together, pressure changes more over a given distance. Wind is influenced by pressure differences, but terrain, friction, and the larger circulation also matter.
Fronts
A front marks a boundary between air masses with different properties. Front symbols indicate the boundary type and usually its direction of movement. A front is not a precise line where the same weather occurs everywhere.
Compare map time, coverage, and scale before comparing two products. A regional forecast and a local observation answer different questions.