'Very often', my customers are contacted by persons claiming that their site is not 'optimal', that they can improve the SEO ranking etc.
As most of the sites I make are not very 'commercial', we do not really have a budget for 'marketing'.
Anyway: Is there some guidelines about how to set up the site 'OK' ?
( I am not talking about 'daily use', like having 'good descriptions' and naming the images properly, but more about the actual setup of the site')
it depends on what you mean by "OK"; there are some tools online that help check for some obvious things:
but you have to take those reports with a grain of salt always.
For clients in Norway, you can send them a link to the attached video. Help them to follow the points in the talk.
Use valid html correctly. Plone does this. Remember good titles for your images, it's used for the alt text.
Cache your site with varnish, make sure it is fast. Google loves fast sites.
Make sure your client writes good relevant content others want to look for and read. This is the hard part!
exactly!
and let's not forget about all the JS (Facebook, Twitter, ad networks, trackers, and so on) that customers love to include on their sites to destroy completely your hard work on having an A score on PageSpeed Insights and YSlow: I just gave up on this many time ago, as you can see in the GTmetrix report mentioned above 
I think the problem here is that SEO is a bit of a snake oil business... there are enough charlatans out there and enough site owners who don't understand what is going on.
One way you might consider countering the BS SEO sales pitch is to include it in your own service offering. If you add a bullet point of "SEO services", you can decide if it needs to be an included item or if you want to charge a bit for it, but the end result is that the client feels they have gotten the problem covered (by you), so they are less likely to be taken in by charlatans after the fact.
thanks.
Hey,
@espenmn , Thanks for posting this topic. I was having the similar issue and was looking what to do next.Your replies helped me a lot as they were informative and resourceful.
best regards!!!