The unfortunate thing about art is it's hard to break down into a science. Personally, I prefer a tilted image because I feel like it's more dynamic, but other people prefer perfectly, well, horizontal horizons. I also think lighting is possibly the most important part of a picture (to the point I literally sat in Gpose for over an hour waiting for decent lighting), but some of the winning entries were imo really bland in that regard, so whoever picked those either doesn't find lighting as important or has a different opinion of what good lighting is. You can try to keep to the rule of thirds, or position your composition so it perfectly matches the Fibonacci spiral, but in the end it all comes down to whatever the preference of the particular person picking participants' entries is, and you've just gotta hope yours matches those preferences of whichever specific judge sees yours :/

...That was a lot of Ps.