What kind of light bulb you using? My first incubator was a cardboard one. I poked holes in the side for ventilation and used a 75 watt bulb on a dimmer switch. Make sure you don't use those eco bulbs or energy saver bulbs. They don't emit a lot of heat. To raise the temp use a bigger bulb or higher watt bulb.
Do you have a lot of water in the incubator? Humidity depends on the amount of surface area the water takes up. So maybe get a smaller bowl to put the water in or remove any sponges or paper towels if you are using them. Also make sure there is proper ventilation. Extra humidity will escape through this ventilation.