No need to SHOUT Welcome to the site.

Best place to start? Arguably you are already here.

Search, study and test. Find something that interests you and look at ways to either break it or make it more secure. If you've got CCNA experience you could do worse that starting with ways of hardening IOS, projects like Nipper will find holes in Cisco configurations and advise ways to improve security posture.

Keep learning, reading and testing. And if you get a problem that can't be solved with a bit of Google-fu don't be afraid to ask, most people will help; providing the answer can't be found by punching the same question into Google that is

Good luck and happy hacking