Trying to get back and get better at mapping, any help?

[Powerlord]

I've played doom for most of my life, in many different ways. There's just something so special about the engine, the incredibly precise gameplay, the environments and world you can make in it. I've tried my hand at making maps more than once, but the results were discouraging in my younger years. I've tried picking it back up every once in a while but the cobwebs and rust prove too strong to even get a foothold in doombuilder again, let alone actually improving and working towards the kinds of touching works that I see coming from the community. I figured I might as well ask the community not only some good places to look for a crash course on doombuilder and common mapper tricks, but also advice and places to look for empowering the actual quality of the maps. The main criticism of my maps made years ago was that they apparently seemed fairly 90s in design and boxy, and upon instrospection I think I realized that I usually jammed what could've been 2 or 3 maps into 1 big one and always felt the need to use every single monster, have every single weapon, etc. I want to try working on quicker, snappier maps that flow into themselves smoothly. I've done some very rudimentary work already with sprite edits and custom monsters and the like, but right now I have no interest in learning/mastering those and would rather focus on vanilla mapping and gameplay. In any case, any advice or help is appreciated, and I'm dearly sorry if I've posted this somewhere it doesn't belong or did something incorrectly, I'm not a forum user for anything so it's all new to me. I hope to have fruitful conversations with you all that may spur me to give back to the community a fraction of the experiences that their maps have given me over the years.