The IRS does some processing after accepting an e-filed return but before they mail you the refund. There are a variety of things they check for - verification of identity being prominent now.
The IRS will either send you a letter asking you to clarify something on your return, a letter asking you to accept a change that they have made to your return, or (if they don't find anything), just send you your refund.
There is nothing you can do to speed this up - just be sure to watch your mail box (this is all done by US Mail) for a letter - or hope your notification is your refund.
