Аз използвах следното парче код:

<ul class="title-author">
    <li class="single-element-form">
        <h1 class="title-form">Blog Post Title:</h1>
        <input type="text" value="" placeholder="Title" id="title">
    </li>
    <li class="single-element-form">
        <h1 class="title-form">Author:</h1>
        <input type="text" value="" placeholder="Author" id="author">
    </li>
        <h1 class="title-form">Content:</h1>
        <textarea class="content-field" typeof="text" placeholder="Content" id="content">
        </textarea>
        <br>
        <button id="create-request-new-post">Publish</button>
</ul>

а в класа single-element-form задаваш да са ти inline blocks ето така:

.single-element-form{
    display: inline-block;
    width: 40%;
    padding-top: 10px;
}

Надявам се да ти помогне.