While over or under watering tends to be the most common problem new succulent growers face, there are a few more issues you may run into. Some common succulents that easily root in water include Jades, Sempervivums, and Echeverias. They'll often be "root bound", which means that the roots are taking up too much space and the plant is unable to grow any more. A smaller pot will dry faster than a larger one. A direct sun can dry out plants and turn their leaves yellow to green, which could be an indication that your plant may be dying.