LCD not working with Arduino Uno
There are 3 things you can try. 

1.
If you have any male pins, solder those to the lcd screen, then stick it in the breadboard. After that you can stick the wires in the breadboard appropriately. The first time I tried this the wires were either touching or not connected enough to the lcd screen.  

2. Double check all the connections made. This also happened to me, just make sure all the wires are in their right places.

3. Have you tried adjusting the potentiometer? Thats what its there for. Try turning it slowly both directions to adjust the background and letter brightness. 

From the looks of the picture, number 3 may be your problem. Try that step first, and if it doesn't work you can try the other two. Hope this helps!