How do I lower the humidity in my room?

I just recently built my Uromastyx a 100 gallon tank, and even before i put him in the new tank, the humidity in the tank is steadily staying at 50-60% and can even get up to 70. I had a fan blowing on top of the tank and everything. I think that my room is just too humid and i'd like to know how to lower it. Just, ugh, can anyone help please, I'm pretty worried about little Pinecone!