general stuff There were never any doubts in my mind: I always considered mapping as a form of art. The exact definition of art is always a topic of debate but most people tend to associate it with something man-made that is beautiful or create emotions. I know what you are thinking and I will kick this idea out of your head from the start: there is no "mapping with emotions". You can feel them when watching beatmaps and they can initiate a creative process, but what is used to make objects work together as you wish is your memory and axioms you set in your mind to guide you mapping.
what makes a map good technically speaking Axioms are usually based on three aspects of mapping : rhythm, visual and gameplay (on a personal note: my experience taught me that you can't be satisfied for too long with your mapping when neglecting one of these aspects). The way you respect them will be what is defined as the "coherence" of your mapping. Gimmicks, resulting from axioms, usually are what makes your mapping stands out as they are the fruits of your personnal experiementations and inspirations. They can be taken from other maps and reinterpreted or created from scratch if you are a mapping genius. To be considered as such they need to be well defined (recognizable) and recurrent through sections of the map.
advices Sometimes, the axioms you set can be too restrictive and reduce drastically your possibilities to prioritize what i would consider useless details (for example: overlaps/blankets with objects that doesn't appear on screen, sometimes people are so obsessed with these they can't see the inaccuracies currently on it). Never think that others will like something in your map that you dislike yourself: if you don't feel satisfied with a pattern you did, redo it until you do.
fulfillment How can you progress and feel fulfilled in your career if you don't finish your maps? You can't. The 15 seconds twitter preview is nice for a quick dopamine rush but doesn't last long, while a finished map marks a step in your career and is something you can move forward from. Force yourself to finish your maps, you might not become a famous mapper but you'll feel more fulfilled that some of them.
about teaching mapping I find teaching mapping only one way unsatisfactory, you need to understand first the goals of your mentees in order to teach them the right axioms/gimmicks. You have to know that there is no unique right way of mapping and that the most important thing before what the others think of your mapping is if you like it yourself. Therefore, teaching how to analyze beatmaps your mentees like is way more efficient.
mapping analysis Ranking system makes mappers focus on modding which is more oriented towards finding flaws in maps, things you DON’T LIKE and why you don’t like them. It forgets to makes you wonder about why you LIKE things, which create a bunch of lazy people missing out on opportunities to improve by truly understanding a map. Understanding why you like/dislike certain patterns is essential to reproduce them properly (im not saying something revolutionary you probably do it without really thinking but i thought it would be interesting point it out).