Most psychology journals require that papers follow the American Psychological Association's style guide. This guidebook covers everything from the structure of the paper to the right way of formatting section headings, and it is updated every so often.
The sixth edition was released over the summer, and it seems it had to be recalled due to "errors and inconsistencies."
I haven't actually seen the 6th edition myself (I just bought the 5th edition a couple years ago and am not in a hurry to buy the new one). On the whole, it's a good manual and the rules make sense. However, reviewers will sometimes thank you for breaking the more frustrating rules , like the rule that charts and tables should be appended to the end of the manuscript -- not included in the document itself. This probably made sense in the day of type-written manuscripts, but makes modern electronic manuscripts very hard to read. Electronic documents are wonderful for many things, but the ease of flipping back and forth from one section to another is not one of them.
Hopefully the 6th edition fixed some of those out-dated rules. But I'll wait to find out once the fixed version appears.