Poppets have been used for a long time to help work magick, and assist with healing. They are pretty simple to make as well.
There are so many different ways to do this. I am going to describe a very basic way but feel free to get creative with it and expand upon it.
Take a piece of white cloth, preferably silk or cotton, and draw the outlines of two doll figures. They should be about 6 inches in height or larger. Cut out the two shapes and sew them together using thread of a color appropriate to the energy you are wishing to raise. Leave a gap at the top of the head so that you can fill the Poppet. You really can use any color material you like. You can have the color correspond to what you are trying to do. For instance if you wanted to do one for luck you could use green. White is a nice basic color for a healing poppet. I especially think these are nice for if a little one is sick. You can make them a cute little one, decorate it and fill it with soothing herbs such as lavender and chamomile to help sooth them when they are not feeling well.
Fill the poppet with the herbs, adding a few drops of an essential oil if you wish and complete the last few stitches to close the gap. Use herbs and oils that are appropriate to what you are trying to use the poppet for.
I have also seen very complex ways of making these. As with anything you will find lots of variation. You can make them to represent the person you are trying to heal. You can add personal effects from that person. However I don't feel it's always necessary. As with anything it's your path and you adopt what you wish. When making one for my little ones I would make one that looks cute and appealing to them. Fill it with herbs energy and love and give it to them. In my opinion the intent that you put into the poppet is far more important then the composition of it. Have fun with it! And have fun exploring all the different ways.