What to read about Arduino development for writing optimal C code?

Question

Arduino

The crux of the matter is that I'm new to C and the code ( in progress ) is pretty unwieldy. It currently takes up 80% of the Arduino Nano's available memory, but there's still a lot to cut in terms of functionality.
What are the ways to optimize in terms of memory for the code?
What should be read on this topic?
Maybe you need to completely abandon the Arduino and take a controller with more memory?
There is no need to talk about premature optimization. I know about it.

Answer 1

Your main memory consumer is the Adafruit_ST7735.h display library, and there are some external fonts. Look, maybe there are alternatives, albeit with fewer features, but not so voracious. Or take mega instead of nano.