Keep "Capture Filters" in mind. If you know exactly what you are looking for, this should reduce noise and shorten loading times later on.
tcpdump [OPTIONS] [DISPLAY_FILTERS]
-i: interface to listen on
-r: read raw packets from pcap file
-w: write raw packets to file instead of displaying them
-n: only display numeric addresses
-X: print packet contents along with headers, in hex and ASCII
and/or: chain multiple filters together
host [HOST]: display traffic transmitted to/from [HOST]
port [PORT]: display traffic transmitted to/from [PORT]
The volume of incoming/outgoing traffic to/from a specific IP address can be monitored using iptables
iptables -I INPUT 1 -s [REMOTE_IP] -j ACCEPT
iptables -I OUTPUT 1 -d [REMOTE_IP] -j ACCEPT
iptables -Z
iptables -vn -L