not really a trick but making sure your seed stock isn't old goes a long way. I've tried soaking seeds but I'm not sure it helped that much with germination rate. I might suggest an on and off heat cycle to replicate day and night temps but that may just decrease gemination time.
I never did get Datil peppers to make any comparisons. I started these plants way too late in the season. By the time the plants were big enough to start flowering the Texas heat had already set in not allowing them to set any fruit. The Ebay Datil did try hard and set 1 decent pod but then...
I put plants in the shed when it gets really cold. A milkbox heater at the lowest setting (freeze protection) will keep my wife's ivys, money tree and other plants alive.