When you make jello in a mold the hardest part is getting the jello out of the mold without messing up the edges are breaking the jello. One trick is to add an extra packet of gelatin to your jello mix when you are making it, this will make the jello firmer and less likely to break. The second trick is to use a hair dryer on the outside of the mold when you are trying to get the jello out. It should only take a couple of seconds to heat up the jello slightly so that the bond between the jello and the mold is broken and the jello slides right out.