For an example of how we structure our HTML, please see our Gulp template which can be download via: Gulp template
Our HTML should be coded using functional HTML5 markup, semantic and pass W3C validation.
We use an indent of 4 spaces in our HTML (keeping elements aligned) and we comment where possible (functional comments if we feel it is necessary for any third party developers who may be working on the site).
We do not waste HTML, thus for example instead of:
<div class="logo">
<img src="name.jpg" alt="Name">
</div>
We would use (if possible):
<img src="name.jpg" alt="Name" class="logo">