You might want to indicate that fields in ASP.NET MVC3 is required visually.

It’s easy thanks to the HTML attributes that the unobtrusive validation API generates.
Start by adding a new CSS class in your site.css called something like .required-indicator.
.required-indicator { color: red; font-size: 1.2em; font-weight: bold; }
Then add a small jQuery script somewhere (in the layout or an application.js):
$(function() {
$('[data-val-required]').after('<span class="required-indicator">*</span>');
});
Done! Here is a sample fiddle.