Short answers, pulled from the story.
The 1937 edition of The Hobbit contains a hand-drawn map of Wilderland stretching from Rivendell to the Lonely Mountain and Thror's map handed down to Thorin. These maps feature three-dimensional Misty Mountains, Mirkwood symbols mixed with spiders, and two rivers decorated with spider webs.
Tolkien worked on squared paper where each square measured 2cm by 2cm representing 100 miles across north-west Middle-earth over many years. He created a detailed design on graph paper that he enlarged five times in length before his son Christopher drew the final contour map.
Allen & Unwin commissioned illustrator Pauline Baynes to paint a map of Middle-earth in 1969 using copies of draft maps plus annotations from Christopher's 1954 map. Allen & Unwin published Baynes's map as a poster in 1970 decorated with header and footer paintings showing characters.
Geologists Robert C. Reynolds examined Tolkien's illustrations in 1974 followed by William Sarjeant in 1992 who noted mismatches between maps and plate tectonics processes. Mountains form mainly next to subduction zones or where continents collide yet Mordor stands as an egregious instance with its square plain fenced by mountains at right angles.
William Morris published The Sundering Flood in 1897 featuring a frontispiece map showing a city on a great river which defined a wholly invented world containing The Wood Masterless and a Desert Waste. Jonathan Swift included maps in his 1726 Gulliver's Travels offering another published example while Robert Louis Stevenson provided adventure story maps in his 1883 Treasure Island for further inspiration.