1) Open the picture you wish to brighten, for this tutorial you will need the layer panel open. Drag the background layer to the duplicate layer option. Here is an example of what step one should look like.
2) On your layer panel you should have two background images. Click on the original background image. At the top go to filter>Blur>Gaussian blur. Example.
3) In the popup window change the radius to about 2.9 or 3 pixels. Than click ok, since there is another background layer on top of the original you should not be able to notice the blur. Example.
4) Change layer 2 to soft light instead of normal which should be the default setting. Example.
5) Than lastly duplicate that layer and change soft light to color dodge, creating a brightened and a more dynamic picture. Example.