Assuming you want to render a component presentation on a PT.
To render a component presentation selectively, you need a way to identify it. If you want to do it based on the component title, you can do it like below:
<!-- TemplateBeginRepeat name="Components" -->
<!-- TemplateBeginIf cond="Component.Title == 'MyComponentTitle'"'[Insert Component Title]'" -->
@@RenderComponentPresentation()@@
<!-- TemplateEndIf -->
<!-- TemplateEndRepeat -->
Read more about the Dreamweaver Templating here