You use LEDs everywhere, here are some ways to make them better.
Ping Pong Light Diffuser
Sometimes you got a really bright LED that you want to diffuse. A simple way to do this would be to take a white ping-pong ball, preferably dented, and using a small screwdriver, punch a whole through the dent. You want to make the hole big enough such that you can fit in the LED, but small enough such that it rests on the lip of the LED. You can then secure the LED in place with tape or tack. For a more permanent solution you can also hot-glue the ping pong ball in place.
Blinken Testing Lights
Burnt out your fifth LED because you forgot to put a resistor in series? Solution: Solder a resistor to one of the leads of your LED. Now you'll never burn it out. I suggest something in the range of 330 ohms to 1k.
I will update this small guide as and when I find better improvisations to LEDs.