SEO writing - How to prove it?

Short intro: Hi - I'm an experienced content writer with 5-star reviews, portfolio etc.

Recently a potential customer suggested we talk via phone. I accepted. He explained to me his needs and at the end of the call he kept asking me if I know SEO, how good I am with SEO, if I use any softwares, my techniques etc.
I replied to him, but in my mind I was thinking "dude, I mean...is this an interogation?"

So, why I started this thread: Could you please share some answers to the question "Do you know SEO writing?"

I mean, I study some SEO specialization already and I keep myself updated and informed. If you wish to share your tips, write them here.

Much respect to the members.

If that is what they are like before you start work, imagine what they are going to be like when/if you start work?
If may well be best to move on to the next client as this one is not worth the aggro.
Just my bitter experience when starting out - this sounds like a client from hell who will probably 'negotiate' (bully) your rate down or 'start off with a trial article' of 2000 words...

Move on...

These days to write articles and to know seo is the best combo.
You must know keywords density.
If you know how to write about one subject, your piece of content can rank on 0# position on google (snippets), even above ads.
Maybe this is what the guy asked you... But I guess you know everything I wrote above.

Are you not sure that he is trying to converting you in doing something else? Because you already write articles, maybe he can guide/help transform you into a VA for his needs witch can be good for you, because you can get new skills...or maybe not.

In internet marketing all I can say is to be OPEN MIND person and try to filter the information.

Much respect to both of you for helping. I really appreciate your contribution. It inspires me.

Your client is talking about On Page SEO. If you need to bring more readers for your content,then this is the best way to do it.

A few quality backlinks are much better than a bunch of bad low-quality backlinks. High quality sites that are authoritative and rank high in the search engines will be the way to go for your good links back to your site.