Server Help/Tips?

Hello, i started a minecraft server about two weeks ago and at first i was getting alot of people on but none of them seem to stay for more thank 45min. Now im posting my server on planetminecraft but nobody even joins my server now, i don't know whats wrong my server seems to be fine but people won't even join it anymore? So could i get some comments that could give me some tips? or even join the server and help me out?
IP: 66.85.185.178:33351