I use tabs for indentation then spaces after that if I need to offset a line by a specific amount of chars, such as a multi-line output or something.
Edit: to be specific: https://pastebin.com/un6iUmEp . Notice how line 3 has one tab, then several spaces before the first non-whitespace character.
I like to use asterisk spacing.
void main() {
/****/for (int i=0; i <10; ++I) {
/********/printf("hello world\n");
/********/printf("%d\n", i);
/****/}
}