Sorry for the late reply, I must have missed this question.
One of the updates ruined the iron dagger method. If you're using that guide here, it probably needs to be updated to better reflect that.
For the fastest leveling, make sure you have the Warrior Stone active (20% faster), and are well rested (+5-15% faster). Crafting is going to give you more experience than improving weapons or related sub-skills. Here is an excerpt on crafting from the wiki:
Because of the flat 25 XP for each item created, it usually is of greater benefit to craft many cheap items than few valuable items. For example making 5 Iron Daggers requires 5 Iron Ingots and gives (38.4 × 5 =) 192 XP. Making one Iron Armor uses the same amount of materials but yields only 94.2 XP.
Making gold or silver jewelry can quickly level up smithing without perk investment. Players can cast Transmute Mineral Ore to convert iron ore to silver ore and silver ore to gold ore. An Iron Dagger (10 gold) yields 38.4 XP per ore chunk, whereas 2 Gold Rings (150 gold total) yield 51.5 XP per ore chunk — 34% more efficient smithing XP gain, along with Alteration XP from the transmuting. [verification needed — these values were changed] Halted Stream Camp has a free spell tome and lots of Iron Ore.
Combining gold or silver ingots with Gems increases the value of the item and thus the skill gain. For example, using an additional Flawless Diamond to craft a Gold Diamond Necklace (see Jewelry) boosts XP yield to 163 XP per ore, albeit Flawless Diamonds can only be obtained after level 40.