Maybe this thread should really be called how to try to raise them fully aquatic, then fail and give them some land areas so they can please themselves! Anyway, the tweezers are just normal eyebrow tweezers from the chemists, nothing special at all although i now use cocktail sticks most of the time as they can be bent and shaped to offer the food under leaves or weeds where the babies feel secure and are most likely to feed. after a while most have learnt that disturbance means food but i still have one or two that are shy and need to be fed with the light off with minimal fuss. What kind of worms are you offering? I've found that normal small earthworms are their favorite by a long way, they will eat Dendrobaena worms only if they are very hungry but red compost worms are never accepted so it may be best to offer normal earthworms until yours are feeding more confidently. I will try to get some pictures of how i feed mine if i can!
Hope this helps!