Infinite skill level gain
This trick requires that you own a house with an alchemy lab. Obtain the Oghma Infinium book, but do not read it. Go to your house, and open the bookshelf. Read the Oghma Infinium book, then select the skill set to assign the skill gain. Close the book, but not the bookshelf. Store the book on the shelf, then take the book back off the shelf, and select it, but do not read it. Repeat this as many times as desired to get as much skill level gain as desired.