The main thing you can do without taking them totally apart is to fluff the wicks a bit. I use a dental pik, but some kind of thin curved instrument will work, or even a tiny eyeglass screwdriver. Remove the white mouthpiece and then the thin silicone ring. (be mindful of the coil and ceramic housing). Then use the dental pik to lift the curved part of the wick (where it feeds into the cup) up to level with the top of the ceramic or a tiny bit higher.
It's easiest to fill it in this state....drip the
juice in along the sides of the plastic, but don't over flow juice over the ceramic cup. Replace the silicone, lining up the grooves with the wicks. I use the blunt end of an eyeglass screwdriver to tamp it back in place, but I leave more room (ie: don't tamp the silicone ring all the way down...more like halfway...just enough so that it is over the edges of the ceramic cup)
It's a bear at first, but very simple once you get the hang of it. Enjoy!