You are right If we think logically the owner is providing the Guest services then why he will considered as a registered member?
Choose a blog, write a guest post. Make it clear that the topic on which you are writing wasn’t published before on the blog. Make your content new and unique. Don’t afraid of being rejected by the author. In chance your article get rejected, you could apply for the guest posting on other blog or you can publish it into your blog. If get rejected ask for feedback, some blog owner are kind enough to give feedback and are of improvement.
-The fist is find relevant websites or blogs and contact the owner asking if they’d be interested in receiving content from us.Finding websites is simple, all I do is go into Google and shop around for websites in my niche. All I do from this point is pick one that doesn’t seem too big(usually only happens when it’s a corporations website) and find a way to contact them. Usually there will be an about me page or contact page, especially if it’s a blog.
-The second is a cool way to find people who are searching for exactly this… guest posters on their own blogs and websites. There is a website called Blogger LinkUp where you can enter into a system to have either 1) your requests for guest posts sent to thousands or 2) your titles of guest posts sent to thousands.
Hope It will useful with you:)
Its Easy... Look a for a guest postings sites.. mostly call web 2.0 and make your posts.. its fun.
Search them with relevant keywords of the domain plus "guest post" "write for us" and these sort of phrases used by websites that have a form dedicated to people who want to write guest posts. Make a list and start sending your content proposals to the most relevant sites.
Best of luck!