Well, use a map of course. ;)
Making maps is something I loved to do as a kid and I can tell my pupils loved it too when being asked to draw maps leading to secret hidden treasures on some island yet to be discovered!
And I found that it still is a wonderful thing to do today - only with other media at hand than back in my childhood days. ;)
Another art journal card (measuring 4x6'') I did using rubber stamps and designer paper (from 7 Dots Studio's "Destination Unknown" collection), Brushos, old book pages that had been coloured with washes of earthy tones first, white Gesso and a black china ink pen.
As the Brushos always re-react when getting wet (which also happens when getting in contact with glue for example) this is a rather "accidental" technique in which you have to either embrace imperfection (which gets a loud "YES" from me) or simply wash off too much colour by adding clear water with a soft detail brush and dabbing it all off with a piece of dry cloth.
You can of course also seal your piece with a spray-on sealant before continueing to work on it. But I actually like how the blue spread on the glued on pieces as well and made them blend in this way.
The dictionary pages had been lying on my desk for ages. I had painted them with some left over colour washes for a different project (as I hate to waste anything)...not knowing what to use them for back then. But they make a beautiful mainland, don't they?
Hugs and happy crafting,