I'm not sure but you may be having the same problem as me, In Halo (near the end of halo 3) I new every single possible glitch, block, angle, spot,weapon capability etc. So what ever I thought of making I could make it to the best that Halo 3 could offer. Now in reach I'm still learning blocks names and that landscape isn't imprinted in my brain so whenever I try to make a map I think there's probably something I could be doing better to make this map better meaning I could spend all this time forget something crucial and someone make something similar and it will be a lot better. The way I countered it was to make bunch of crap maps that I know wouldn't be good for practice maps (excuse if it turns out crap and just try and learn as much as you can. But to be honest I don't think my problem will go away for awhile till i see more maps and learn stuff off by heart.