... take a little time and learn how to set the mixture. Start with gas then add in the oxy. You'll see the cone sharpen up and there will be a yellowish outer cone, a blue middle cone and a white inner cone. Keep adding oxygen till the yellow cone disappears into the blue cone. I like to set mine so there's a slight wisp of yellow visible around the outside of the blue cone.
... Devil is in the details, these'll get you there.