Wearables In progress: My first attempt at a petticoat - please critique

Learning to sew on your own can be fun though
The reason you arent getting enough poof is because your cloth part is too long, and theres probably too much tulle excess sticking up into the skirt.
What I would do is cut off the excess tulle above the hem inside the skirt, and that will probably give you more poof.
But very nice for a first attempt ^ ^

 

You're right, you really do not have enough tulle for a poofy petticoat. Next time, make your yoke (the woven cloth part) more fitted. The yoke should end where you want the fullness to start. Cut a much longer rectangle of tulle and gather it along one of the long sides. when you pull up the gather thread, you should be in a better position to judge whether you have enough tulle. 3 times around your doll is a minimum. If it does not look like enough just cut another piece and add it to the already gathered strip.

I am sure it must be difficult with no one to teach you. There are a lot of tutorials on the web but it is hard to find them if you do not know what you are looking for. If you are unable to find a tutorial ask here and someone with a bigger sewing vocabulary will help you find what you need.