application support to development

Question

hi, I have been working in support role and been continuously studying dot technology , I have been in to application support role as L1 analyst , but now I want to move in dot net development or at least L2/L3 profile in web application support, I want to know how should I proceed so that I can convince the next company that I am ready for a developer or L3 role in asp.net application development , I want to know what are the topic should and concentrate (I.e iis ,C