Welcome to gardening and don't fret about your past mistakes with the Aeonium plants. These are succulents that need bright light and little water. The number reason for failure is too much water. Letting the potted plants sit in drainage water is also dangerous as they can suffer from root rot. How much to water is dependent on how much sun, the size of pot and the type of soil but in general these succulents require watering just a few ounces as little as once a month in winter when light is low but in summer they may need watering once a week. It is best to poke your finger down into the soil and do not water if you feel any moisture. Falling leaves is often a sign of too much water. A wilted look to the plant could mean the roots are rotting from too much water.   These succulent plants also prefer to grow in a clay pot with a soil mix that includes extra grit or perlite for added drainage. You can also use a houseplant soil made for cacti. Most succulents use very little fertilizer so use any plant food at half strength just once a year in spring. Keep growing, Marianne Binetti