Here's one that I've found useful over the years. Pretty easy to do. Make those 'required' fields stand out when it comes to ticket submissions. This does require template edits
Step 1:
Open up whmcs/templates/template/supportticketsubmit-customfields.tpl, replace it all with
PHP:
<div class = "form-group">
<hr>
<label class="col-sm-3 control-label" for="customfield{$customfield.id}">Custom Fields</label>
<div class="col-sm-6">
<p class="help-block">The following custom fields are available. Those marked in <b><font color="red">red</font></b> are required</p>
</div>
</hr>
</div>
{foreach key=num item=customfield from=$customfields}
<div class="form-group">
{if $customfield.required}
<label class="support-required control-label" for="customfield{$customfield.id}">{$customfield.name}</label>
{else}
<label class="col-sm-3 control-label" for="customfield{$customfield.id}">{$customfield.name}</label>
{/if}
<div class="col-sm-6">
{$customfield.input}
{if $customfield.description}
<p class="help-block">{$customfield.description}</p>
{/if}
</div>
</div>
{/foreach}
CSS:
.support-required {
width: 25%;
color: red;
font-weight:bold;
float: left;
min-height: 1px;
padding-left: 15px;
padding-right: 15px;
position:relative;
}
Of course, you want to edit this to taste. this is just an example of how this can be done