I have bought two domains mysite.com and my-site.com what i have to do for saving myself from penalizing by SE for keeping same contents.Which domain should i submit to SE and the step by step SEO for that domain and what i have to do with other domain ?
You don't need to submit new sites to search engines anymore. A link to the site will get it indexed faster. Don't put duplicate content on the sites - either do something different with the second domain name or just point it to the first one.
Decide which one is the main site and write different contents for the other one and link the latter to the first one. That's to keep matters simple.
Maybe i haven't cleared my point.Actually i have only one website but two domains as i said difference is only of one dash "-" . So which domain name should i consider as important for SEO and what to do with other [i mean how to redirect it to main SEO favourable domain name].