When you begin any ability from OSRS Gold scratch, it's better to undertake a quest that is related to the skill for experiences in the quest. Through a Knight's Sword quest that takes less than 10 minutes, you are able to gain 12 725 Smithing Experience which will get us from the level of 1 to 29.
All you need to do is start it is level 10 Mining. The requirements for this quest are low and doing this quest is definitely faster than the regular methods of training. Also, if already an experienced player and have already reached level 20 in Magic, 20 levels in Mining, and level 20 in Crafting it is possible to finish both aspects of the Elemental Workshop quest.
This will take you straight to level 35 without having to worry about any other Smithing methods for leveling. If you'd like to keep the quest later on, you can additionally complete Giant Dwarf quest which later will be required for various methods. There's several other quests like Recipe for Disaster, Devious Minds, Cabin Fever, Elemental Workshop II, Family Crest, Fremennik Trials you can take for the best adventure. Take note that these quests require membership, therefore f2p players can't complete them. Sadly neither free to play quest rewards players who have Smithing experiences.
LEVELS 29-40 IRON ITEMS. In this level bracket, you'll want to make the best possible iron products using iron bar you can make - similar to Iron Platebodies. Leveling up to 40 should take you around an hour and about 1000 bars being used. The best place to do this is at the western Varrock and you can begin making the pieces you need of Armour there.
LEVELS 40 99 GOLD BLAST FURNACE. The most rewarding experience rates you can earn are smelting gold bars at level 40 in the Blast Furnace minigame where you can smelt gold bars which is why many people are doing this. Utilizing Goldsmithing Gauntlets during Buy RS Gold this training technique is essential since it greatly improves the experience rate as well as gp per hour.