The Drills, Practice and Penmanship board has a lot of exercises you can do ( greggshorthand.proboards.com/board/3/drills-practice-penmanship ). There have been drills placed on there due to questions in the Shorthand Q & A board. These are great to study for a day or up to a week. Even if you know the theory, there are several words, sentences, etc., in that drill to help with learning it thoroughly.
If you find that there isn't a drill there and you would like one, you can start a new discussion with the words you know. I may add more and other's can if you would like.
If you need help, ask in the Q & A board ( greggshorthand.proboards.com/board/20/shorthand-talk ) which gets more views and replies due to being near the top. I will probably add drills if I get a chance for further study and review of the theory. Sometimes even the most advanced may need help. Especially if you haven't used a theory or word for a while.
"Advanced" questions can be asked on this board if you prefer.
"Gregg Shorthand had achieved the most extraordinary success ever attained by any system in the history of shorthand." John Robert Gregg, 1922