I own two web domains that one redirects to the other one. Should I get more domains to increase SEO ranking?

no, i don’t think that would help unless you advertised the name you are having redirected. Actual domain name has litle to do with search rankings, it is content that gets you a good ranking with the search engines

Work on your main site. Content is king.

Real estate is a hard market, especially now. Find your niche and concentrate on that. If your area is Mayberry, South Carolina then concentrate on that area. Write articles about that area and what people may like about it. Then get links to those articles and your website. Use good title tags and don’t spam.

This will not improve the ranking, just by adding more domains.

But if you purchase the similar domain names and redirect them to your main site, then you will get some extra traffic when people will try those similar domain names.

Thanks,

Also, it seems like Google may penalize if you redirect too many domains to your site (10-15 in my experience).

A site the immediately redirects to another site will be viewed as duplicate content and filtered. If you want the second site to rank you will need to produce unique content on that page. It’s ok if all it’s links point to your other site though (hint hint).

Good Luck