Header organization question

I've recently been included in a midsized C project with many .c and .h files. The problem that I'm having is organizing the #include statements so that there are no circular dependencies, which are causing problems with our compiler. The project has used the #ifndef statements, but we are still getting errors.

I was wondering if anyone knows a good standard for organizing .h files and #include's so that all the dependencies are easy to follow. Thanks in advance!

Instead of reorganizing the #include statements, you could consider to reorganise the contents of the header-files. If you have error with the header-files, it is often easier to reorganise the contents of the header-files than finding out how to organise the #include statements.