How do you take a cutting off of a tree? I want to do a cutting from my Mum's Tulip tree but have no idea what I'm doing.

There are any number of ways to take cuttings, more than can be covered here. For the tulip tree I would do an air cutting since it is a hard wood. That's a bit complicated for a new comer to rooting. You might want to try this method: 1st make sure your clippers are sterile and very sharp. 2nd find green sprigs at the end of branches (New growth gives me the best results.) Try to get at least three inches of green growth stems. Cut the stem at a forty-five degree angle dip in in cutting powder wrap with clean damp paper towel strip immediately. Then continue to make more cuttings sterilizing between each cutting. Dip and wrap just like with the first. I make six cuttings for each one that I want. If I have to many at planting time I give the extras away. Do not let the paper towel wraps dry out. Place all of your cuttings in pots with a mixture of new potting soil mixed with an equal amount of spaghum moss. Put the cutting in still wrapped to get rooting mixture in place. Keep the soil very moist at all times. When each developed strong roots plant in location desired. Keep well watered the first summer.