Edit in JSFiddle

p.sample1:before {
    content: url(http://msweb.moo.jp/wordpress/wp-content/themes/d-siori/img/sample_icon01.gif);
    margin:0px 10px 0px 0px;
}

p.sample2:after {
    content: "【必須】";
    color: #ff0000;
    font-size: 90%;
}
<p class="sample1">サンプルです。</p>
<p class="sample2">サンプルです。</p>