In a collaborative programming environment it is always good to have a set of coding standards that you follow.
Thankfully, WordPress have coding standards which all developers should try to follow.
If you peek at the WordPress source you will notice that (almost) all code follow this standard, which makes it very easy for other developers to read the code.
Take a look at the section discussing shorthand PHP tags, an issue I have written about previously. Space usage is also a very common mistake among developers. The correct space usage can really improve your code’s readability.
Codex: WordPress Coding Standards