Hi Richard (nice name ),
We have several standard templates available in our company, all pretty simple and outdated but also all responsive. We have tested designed creative templates build by an external company vs our standard templates and most of the times our templates scored better in regards to open/click and follow-up. Main point which is important for the consumer/customer is that the template is clear and the CTA is easy to see but also to click. As already mentioned by yourself always make the templates responsive.
Our basic template consists of the header and in the body simply a hero image (lifestyle or product image in our examples) with a title and optional sub title below that. Right after it contains a CTA and below that some copy in regards to the topic of that email and the footer. Of course Eloqua is much more than just email so also make sure the same look and feel is used in the other touch points (Landing pages, social etc.). In the end you need to have a relevant consumer journey in the same look and feel for all touch points.
Success in your email design is of course not only achieved by a good template, be relevant to the right consumer on the right time!
