How to organise large code files?

Question

I am increasingly aware that my code in any single file can often span hundreds of lines quite easily and although I know the implementation might be sound, it still feels messy

Answer 1

I go on the theory that if you cant see an entire method on one screen (i.e. you have to scroll), you should break the method up into further methods - either in the same class or when the code will get used more than once into a helper class.