Time is of the essence once you have had a job opportunity advertised for a few weeks, especially because you are attracting the connected generation, who will lose interest when responsiveness is lacking. I suggest you include a closing date for applications, but start the selection process as you start receiving applications. The first ones to respond tend to be actively looking and may have had your company on their shortlist of preferred employers. Thanks to the functionality of social media, some search engines allow job seekers to set preferences and follow companies.

If you can thank candidates for their application as soon as it comes in, and respond with a time frame within which you will be processing them this sends a bit of positive news to the candidates. It also lets them know that you received their application and the date by which they can expect to be called for an interview. You can even indicate by when they can assume that they have not been shortlisted...