Most direct inspiration:
First of all, you will need to choose the correct blue
to indicate water. This should not be too watery.
You must remember: people do not like wet feet.
If there is no water to indicate, no matter,
you must still elect a blue. Let me recommend
eggshell, at a push, azure. Choose a symbol
for church/temple/mosque/synagogue. Choose
a symbol for pub.
...
If the area you
are mapping has no seas/lakes/rivers/streams,
I have to question why you are bothering. You
won't get to use that lovely blue you spent so long
deciding upon. Do the Norfolk fens instead. Better
yet, East Anglia in its future state, quite utterly
submerged like a sodden Constable. Come on,
get your coat, I'll show you. You won't need your shoes.
Cartography for Beginners by Emily Hasler