Three most important things for me:
>Keep your and your map's niche clear. One cannot be good at everything without an era of practice, so make sure you know which kind of mapper you're going for (e.g. farm mapper, tech mapper and so on. You can even have it more accurate by adding features. I like simple but exquisite farmy stuff so I always keep that in mind.) at first, and what kind of map you're working on (e.g. calm, generic, jump, deathstream, alt, sliderhell, sometimes a conbination of several of them according to the song but I'll certainly discourage a new mapper to choose such a song.).
>Keep learning from others. The Chinese saying goes "Moments of learning is far beyond days of thinking", so act like a sponge and always absorb from other maps. If you're new and cannot sense the style behind a map exactly, just focus on small things you take a liking to, like a couple of jumps, a combination of sliders. Use them in your own map, and when you think you're good enough to use them properly, go for more. If serious you can even have them on a notebook or in screenshots.
>Keep involved in the mapping community. People here are mostly kind and ready to help you in lots of ways. Stay friendly&humble, keep asking. If you can have someone else to handle your problem, then you'll only organize words to be clear&reasonable. Broaden your social circle is also good when you need some good mods/guest difficulties. I'm just opposite from a social butterfly so the result is over 2 years' struggle and not even one ranked mapset. Don't be like me. From 8/8 to 8/14, the Community Mentorship Program Summer 2021 will open its mentee registration, and if lucky enough you can even find a mentor and progress rapidly.