Well, there can be a lot of variables in hatching. I don’t want to overwhelm you, but here are two pieces of general advice.
#1: Know your incubator. Spend some time really learning its features and quirks. Figure out of it has cold spots, loses humidity in certain weather, etc. (This is where a separate thermometer/hygrometer comes in handy.) Run it empty, maybe sacrifice a few infertile eggs to test it with eggs inside.
#2: Be patient and calm. If you’ve done #1, you’re less likely to really stress when there is an issue. Because stressing out makes the hatches a lot harder on you.
And of course keep checking out the incubation forum discussions. I see new and interesting perspectives all the time.