^^Naming style. Prescription.

lowercase lower_case_with_underscores	function, method, global variable

UPPERCASE UPPER_CASE_WITH_UNDERSCORES	CONSTANTS es: MAX_WIDTH

CamelCase	ClassNames es: SingleVariableIntegrator

camelCase	Parameters, methods, local variables, etc.

Most important thing is to be consistent

Anything consistent is readable after a while
But your brain automatically notices visual differences, and assumes they're important
It actually does take longer to read code written in a mix of styles…
…and the error rate is higher

Names to Avoid

Never use the characters `l' (lowercase letter el), `O' (uppercase letter oh), or `I' (uppercase letter eye) as single character variable names. In some fonts, these characters are indistinguishable from the numerals one and zero. When tempted to use `l', use `L' instead.