For content marketing I'd highly recommend looking at the HubSpot inbound methodology and buyers journey.
You may or may not be aware that users tend to go through something called a 'buyers journey' passing through three key stages that are 'Awareness, Consideration and Decision' with content labelled as Cluster, Pillar and Target.
When it comes to creating content you should try to bare this in mind. For example:
If you were a personal trainer you might do some keyword research and find the following, marking it at different stages of the buyers journey and content type.
Awareness/Cluster Content: 'how to get fit' (the user has an issue that they are trying to find a solution for)
Consideration/Pillar Content: 'personal training sessions' (after researching, they have found a potential solution)
Decision/Target Content: 'book personal training sessions' (after further research, they know what they want/need)
When you have a detailed keyword list with ideas that fall into these parts of the journey it should make creating content a little easier.
In answer to your question:
Just because you're not targeting a specific keyword doesn't mean that you won't rank for it (it will just make it less likely and more difficult). Ideally, you want to create 'Pillar Content' as this will be the main category of a subject. You would then create and link to/from the related 'Cluster Content'.
Google is very good at determining certain keywords and other related terms such as synonyms and something called LSI keywords. If you're not targeting other related terms but mention them in your content, chances are you may get a small amount of traffic from it as long as the content is of good enough quality.
Hopefully this helps?