I am using ArcGIS Javascript API to load the map using MapServer REST url published on ArcGIS Server. I am not using cached services. I am using AGSDynamicMapServiceLayer class of ArcGIS Javascript API to load the map. I noticed that loading map takes between 15-30 seconds. I am trying to reduce this to 2-4 seconds. How can I do that? What is the best practice to configure the map service so, map can be loaded faster.
Make your internet connection faster and the number of layers and features smaller.
Seriously. It all depends on how much data you are loading. You could try caching on arcserver?