When you collect or have eggs posted out it is important to let your eggs settle for 24 hours, ideally next to your incubator. This way the eggs can reach ambient temperature. When storing eggs for hatching you should always store them pointy end down.
Incubator Temperature
Having your incubator checked and running correctly before incubating commences is important. You should run your incubator for at least 24 hours prior to iron out any problems. It is too easy to ruin good eggs by not having your incubator adjusted properly. If eggs reach an internal temperature of 105 degrees they will be ruined. Remember that is internal temperature of the egg, not the incubator. The temperature of an incubator changes constantly but the temperature inside the egg will be an average of the temperature swing in the incubator.
In a still air incubator, 38.5 degrees measured at the top of the eggs is perfect. In a fan forced incubator it should be 37.5 degrees measured anywhere in the incubator.
Having an accurate thermometer is very important. Most new incubators have accurate temperature controls, often with digital displays. Gauge your hatch results and raise or lower the temperature accordingly. If the eggs are hatching late the temperature needs to be raised and if they hatch early it needs to be lowered. As you continue hatching if you keep solid notes of what you have done you should receive better results each time.
Incubator Humidity
Humidity should be 40-50% during incubation and 50-65% during the last 3 days. Humidity does not need to be as accurate as temperature but a bad combination of both will definitely cause problems. Temperature inaccuracy will definitely cause problems during hatching.
Keep in mind too that the depth of water has no bearing on humidity; it is the surface area of water exposed to air. If the humidity is too low add another pan of water and alternatively if it is too high reduce the size of the water container in the incubator.
Turning your Eggs
During the standard period of 21 days incubation, your eggs will need to be turned a minimum of twice a day, 3 is better or more. Most new incubators do this automatically but ensure all eggs turn. If yours is a manual incubator they need to turn 180 degrees each time. Do not turn eggs for the last 3 days of incubation.