Be sure to collect all the info you need to type a reference when at the library. There is nothing more frustrating then starting to type your reference list and finding you don't have enough info.
For journal references you'll need to collect the following: author, title of journal, title of article, vol, issue, pages.
If you are copying articles be sure your copies contain all of this info. Most of this info is usually in the running head of the article. The running head appears at the top or bottom of the journal page.
Traps to watch for:
The running head is on every other page and you didn't copy the page w/ the running head.
The running head doesn't have a key piece of information. Copy the cover page or the table of contents page or write this info on your copy.
The bottom edge or top edge of the article was cut off by the copy machine.