Once your plant is the proper size, you should waiat till your plant has the least amount of nutes in its leaves possible to clone. This means clone after you water the plant, if you have recently nuted the plant, wait. Clones with high amounts of nutes in their leaves take longer to root. To help this process along you can also spray the mother plant down with water a day or two before you plant to take cutting from her, and once again hours before you do. Do all of the above and you will aenjoy a much higher clone success rate.