What's your experience level with running servers? What kind of OS are you running? Have you ever hosted a server (either client run-opened to LAN or actual dedicated server (vanilla minecraft, forge, ftb, etc) before successfully or is your first venture?
I ask because there are literally a ton of things that could stand in your way.
1. You did port forwarding. On what. The router? Did you allow exception on your server machine to allow the port? DId you try disabling your firewall entirely to see if that solved the matter?
2. Are you looking at a server on the same LAN, or over the internet?
3. Can you ping each others IP address? (again this address will vary depending on whether you're looking at a LAN or WAN situation)
4. Is the server log/console showing connection attempts, or is the connection getting blocked before it even reaches the machine? (see #1).
