First of all and most importantly, get more land. I'd suggest 22 if you plan to have high cost creatures like Niv-Mizzet, Dracogenius . (4x Sulfur Falls, and base island/mountain off of your color distribution)
Secondly, you need to decide what you want to do with this deck. Right now it's just a bunch of red and blue cards. Pick a strategy and stick with it, for example: Nivmagus Sniper. It focuses on the synergy between Nivmagus Elemental and Guttersnipe with a lot of burn to compliment. Not saying this is the direction you should go, but you need to have a focus for your deck.