How do you improve smithing really well without using the 'iron dagger' technique? [duplicate]

The method I used to use was a bit of a combination of skills.

In terms of Smithing, the one thing I found to be the most efficient in raising your skill level was making jewellery - particularly gold rings.

Now - before you ask "where am I going to get that much gold?" - here's the second part of my method. The Transmute Mineral Ore spell can be found near Whiterun in a bandit camp called Halted Stream Camp. This is an upper level pell, so you may need to do a little bit of levelling before you can use it effectively. However, the other thing that mine is good for, is iron.

So, using your new transmutation spell, and an abundant resource of iron, you can alter your iron to silver, then gold (boosting your Alteration skill), then craft gold rings, (boosting your Smithing skill), and get you a fair bit of money when you sell them all (as well as a bit of levelling in your Bartering skill).