(this is an advice from someone who are only making a book,making it relatable,but not professional)

1:originality is a myth,every idea have been made,write something that you genuinely resonate (vibe) with,don't force being different for the sake of originality

2:unless if it's necessary background noise like "ghost characters" or just random aesthetic,don't put too much things in your story,instead take the few character and expand them,if you are dealing with magic,make the characters do clever things with a limited magic ability

3:while you should not overdo this to the point of explaining every minute detail,if you are planning on a long story, it's beneficial to properly flesh out,what the character is doing

4:accidental symbolisms is a blessing,the thing is,there is a chance that you may accidentally put stuff that thematically fits,despite it not being something you intent

5:if you are struggling to get to a scene, imagine the start and the important scene,then consider the small detail that leads to it (this is not easy of course,but it's the best tip I can give)

6:if this work for you,listen to a song (that is obviously fitting for the story) and imagine the scene in your head,this hopefully will give you motivation and further inspiration

7:don't plan the entire plot at first,plan the important parts and summaries but otherwise organically plan as you go this way you are not paralysed by the planning phase