Three initial possibilities:
What is the "Effective ppi" of the image in InDesign (look in the Layers panel) it should be around 250 to 300 for printing?
If you've added extra pixels to an existing low res image (interpolation) in Photoshop, it increases the ppi but it will make the image blurry. You need to start with a high resolution image. Just increasing a low res image to 300ppi will not improve it!
Alternatively if it is high res, try changing the View > Display Performance > High Quality Display. (if you have the display performance set to a lower view and the image is the correct ppi.)
You say "attach" an image. You don't attach it you Place the image. File > Place...