The user experience of web mapping applications increases - among other factors - with the responsiveness of the map and its tools. Application loading time, drag and zoom speed, layer rendering and query response time can be significantly reduced, following some simple rules and best practices. This presentation starts with a demo of a simple map viewer that is assembled from snippets of example code. We will then look at script building and loading techniques, OpenLayers configuration tricks, layer grouping, server side tile caching and the combination of WMS and WFS to build a responsive interactive map. Applying these techniques step by step, we will see how the viewer performance increases.