or at least where to start to look for optimization tips?

Well, there is a new tool at adlabs called adwriter [adlab.msn.com] which tries to suggest good adverts for your web page. Presumably the suggestions, whilst not necessarily useful, mean that if you can optimise the page to make your ads LOOK like the suggested ones, then I'd have to surmise that the quality score hits the mark.

thanks Receptional, great tip. so it is as if you are trying to solve a math equation by trial and error.