If I increase voltage or wattage does the light get brighter?

No, brightness is determined by the lumen count. Volts and watts are not a brightness rating. 

Lumens indicate the amount of brightness a bulb emits in all directions. They are usually written in technical specifications like this: 4500LM or 4500lm. The higher the number, the brighter the bulb. 

The brightness of a light is not determined by the amount of electricity flowing through a circuit (volts) or how much energy is consumed (in watts). If you increase the voltage supplied to your product that will lead to the bulb burning out similar to a power surge (and voiding your warranty).