There is a great mapmaking tool available to everyone, and step by step instructions on how to make maps. I encourage everyone to play with it a bit, it's fun to build something and call it your own.
And yes, Koppa's map, Tropical lake, is fun and new. Keep working on it and smoothing out things, work on the textures and make it pleasing to look at after you get down the gameplay you want.
As a note, unless you add mexes or reclaim up to the very border of your 10x10 map, the map will play more like 9x9 or something like that. Most maps don't utilize their full dimensions, due to mountains (open palms, crossfire canal), water (craftious maximus, corsica duel), no reason to move into the outer area (standing stones), or whatever. A 5x5 like crimson feud uses almost all of the map space (mexes in the corners, reclaim in the middle and corners, spawns in the other two corners with reclaim) and for me that's why it's a good 5x5. Nobody would bother moving tanks behind the spawn in open palms if there were no mexes or reclaim back there, and ~30% of the map would be unused.
The reason Lionhardt's Regor highlands is such a great map for me is because of the droppable mexes around the mountains. Without those mexes or hydro, there would be no reason to move onto the mountains around the edge of the map. The effective dimensions would shrink. This may seem pretty obvious but isn't something you will normally think about your first time making a map, so I am telling you now
I will have more time to work on my map soon. Good luck on your map making!
Edit: And thanks Kalvirox for bringing attention to more/new 1v1 ladder maps