/usr/sbin/tcpdump [options] [expression]
So the man page has pretty much all you need, but here are the most useful options:
For an expression, your probably want something like this:
You can limit the noise to just one protocol like this:
host remote.site.com && port 80
You can limit direction like this:
dst host remote.site.com && port 80
host remote.site.com dst && port 80
You can combine expressions with not, and, or, and parentheses. You can pass the expression as several arguments or a single argument, so for complex expressions with parens you may want to just quote the whole thing.
Here's a full example:
tcpdump -s 0 -xX -w http -w - 'host hendrix && port 910'
A nice way to capture dns requests:
tcpdump -i enp10s0 -s 350 -C 100 -nn dst port 53