Apps needed:

Superimpose 

Picsart 

Superimpose:

1. Open your cover and then a white image. Go to transform and use soft light.

2. Now go to mask erase all the white  and use the regular masking tool turn the soft brush on and add highlight where you want it. Save when finished.

Picsart:

1. Open your cover and go to draw change the color to white and turn the hardness all the way down. Make the filter soft light.

2. Draw over the parts over places you want the highlight. (I drew over with black so you could see where I put it) save when finished

I hope you enjoyed this tutorial!! I just think the highlight adds more life's to the photo maybe I'm wrong but it depends on you right preference! Happy editing lovelies!