Take heart, Serama are harder than other breeds. I have hatched hundreds and hatch about 30 per week, so I offer these tips that have helped me.
When your eggs arrive, candle them to see if the air sacs are floating or very large. Old eggs will have a large air sac and old eggs are more prone to a detached air sac. If the eggs are old or damaged, you are starting at a disadvantage but may still end up with chicks.
Keep guages on temp and humidity. If you are using a styrofoam incubator, place your thermometer on level with the eggs. I incubate at 100.5 F at 55% humidity and have good results. If they are joining larger eggs, it may be a disadvantage to them, but it may still work.
Temperature fluctuations are a problem in styroam incubators but you can add a water bladder to even them out - just fill a zip lock or two with warm water to help keep the temperature from spikes and valleys.
Candle again at 5 days and you should see a little red spider-like embryo forming. Toss clear eggs or those with just a blood ring.
I keep turning until they pop out. They should hatch on day 19 or day 20. If they don't pip, candle to see if they are in the air sac - if they are crack the air sac end open and help just the head out. If they don't finish on their own, let them out but take care not to pull the cord out, pinch it off. 2/3 will hatch unassisted in the right conditions, you can save most of the rest by helping.
Be sure to grind their food to a very fine grind so that they can eat it. Do not dip their beaks in water as you would hatchery shipments - they will likely go without water or food for 24-48 hours. I mix 2/9 baby grains (small ground corn and wheat), 1/9 rolled oats (oatmeal) and 6/9 medicated starter in a coffee grinder on the coarse setting.
I hope you have a great hatch! They are the cutest little things!