ss

• -l : Listen flag is not about "watching" but more on whether the socket is a server(listening) or no.

• Netid: nl, p_raw, u_str(Unix stream), u_seq(Unix sequence), u_dgr(Unix Datagram), icmp6, udp, tcp etc.
• State: Only useful for TCP(tcp, u_str, u_seq etc.). For anything else(udp etc.) this should be UNCONN.
• Recv-Q/Send-Q, Local Address:Port, Peer Address:Port: See netstat manpage for details
• Process: Sometimes this will not show up without sudo

I am not making additional cheatsheet for netstat as it's an alternative to ss.