I found an easy way to to level up my Smithing skill up to level 100 in about an hour to and hour and a half (time may vary). Go to Warmaiden's in Whiterun and buy Iron Ingot's and Leather Strips from both the owner in the store and his wife (she is usually located just outside on the forge )

Note: You will need a good amount of gold to do this.

Go to the forge and continuously make Iron Daggers , if your level in Smithing is around 20-30, it should take 2-3 daggers to get one level (you will need to make more to level as your skill increases). After you've used all the Iron Ingot's or Leather Strips , and couldn't be bothered waiting 24 hours (game time) for the shop to restock, go to another town (I chose to go to Dawnstar) and do the same. Then drain that shops stock, and repeat the process either between towns or you can wait 24 hours until the shop restocks.

Note: You will be able to sell the daggers for about 6 gold each to the shopkeeper.