Describing your images with an alt tag (Low SEO value)
A website with no images is boring and dry. You need images to boost user expereince and catch the readers attention.
When using images of any kind, always remember to fill out the alt-tag in the image module in the mono editor. What you write in the alt-tag is not shown to the naked eye, but it helps the search engine to understand what the picture is showing. It's a good idea to find the keywords that describe the picture as precisely as possible - and remember to credit the photographer as well.
There are certain things that you should avoid at all cost if you want a high search engine rankings. One example would be iFrames which are bad for SEO. Search engines have absolutely no way of scanning nor indexing this content. You should avoid using iFrames on your site unless it is absolutely necessary.
Note that the mono tool creates websites in HTML5 - the most friendly form for content when it comes to search engines ability to scan and rank a site. So it's only using special additional code you need to avoid when making sites in mono.