GRID Application development is a hard task. Good applications should correctly use large distributed systems, whose infrastructure heavily affects the application performance. In this paper we propose a performance oriented approach to GRID application development, founded on the use of a prototype language (MetaPL) for the description of the applications and the use of a heterogeneous system simulation environment (HeSSE) for performance prediction. We developed GRID simulation components for the existing simulation environment (HeSSE) and validated them. After that we extended the MetaPL language in order to explicitly support GRID application features and simulated a simple case study to show how the approach works.