Another great tip from Ask a Manager: Don't be misled by application deadlines.
Even if there's an application deadline listed on a job posting, hiring managers may be reviewing applications as they come in ("rolling") or may have a priority deadline when they'll pull all applications but leave the posting up until the position is filled.
Once you find a job that you're interested in, take your time to put together a quality application. But don't procrastinate. Even if a job isn't "closing" for a while (according to the posting), they may be ready to start interviewing now, and if they find someone they love in the first round of interviews they may not even see your stellar application.