The screen should by itself fit perfectly flush if there is no dent in the frame. I used to move over the small metal bracket at the top of the screen near the camera but after someone suggested to leave it I have more success. There are a couple of things you must check:
- Did you fold the digitizer cable correctly under the top of the screen? If not it will sit on the edge under the top and bulge the screen up
- Did you use adhesive all around the top, bottom and edges where the glass is in contact?
- Did you check that the speaker (bottom left corner) is tucked down into the bezel? Sometimes the speaker is raised when you open the metal mid plane. Make sure it is tucked down so it does not bulge the glass on the bottom.
When I follow these steps I get a perfect fit every time. Should not have to wait for the adhesive to cure. It should look perfect straight away. Of course the adhesive will sit even better after some hours. Just use your hands and press down all along the contact parts and the heat from your hands should make sure the fit "cures"
Helpful reading here where we discussed this:
What parts to move from the broken screen?