Hello Profezor
Yes, there are many people who earn a decent living marketing casinos online. It does take time (usually six months to a year to ramp up to a respectable income) and considerable effort. It also takes money. To effectively compete you must advertise and utilize paid placement and pay per click search engines. A word of caution though, 98% of the low end paid advertising promoted online is totally ineffective. So you must choose your media buys carefully. You must also immerse yourself in learning Search Engine Optimization and you must choose and develop domains wisely. You WILL NOT earn any real money using free sites or redirected domains. Since you have a server this should not be a huge issue.
My best advice is to read everything you can here and on the various industry message boards. After three months of operating a portal you may apply for membership to GPWA (http://www.gpwa.net).
Heres the logical progression Learn – Apply – Optimize – Earn
Good Luck