Add the below lines in your Web.config file to Trace your Application
<system.diagnostics>
<sources>
<source name="System.ServiceModel">
switchValue="Information, ActivityTracing"
propagateActivity="true">
<listeners>
<add name="xml" />
</listeners>
</source>
<source name="CardSpace">
<listeners>
<add name="xml" />
</listeners>
</source>
<source name="System.IO.Log">
<listeners>
<add name="xml" />
</listeners>
</source>
<source name="System.Runtime.Serialization">
<listeners>
<add name="xml" />
</listeners>
</source>
<source name="System.IdentityModel">
<listeners>
<add name="xml" />
</listeners>
</source>
</sources>
<sharedlisteners>
<add name="xml">
type="System.Diagnostics.XmlWriterTraceListener"
initializeData="c:\log\Traces.svclog" />
</add></sharedlisteners>
</system.diagnostics>