For the first time, you can switch your world to one of officially Blast Furnace worlds. If you're less than level 60, be sure to carry an RS gold amount of gold as you will need to pay Blast Furnace Foreman every now and then to time. You'll also require stamina potions as you will lose energy after a only a couple of minutes. This method gives amazing experience rates , especially at lower smithing levels but is very costly. In order to level from 40 to 99, it will take about 65mil (after selling bars that were made).
LEVELS from 74 to 99 ADAMANT Tips. Another option to the Blast Furnace, which is extremely expensive is crafting adamant dart tips with adamantite bar. Level 74 is required to create these tips with a small profit. It's not the only benefit of this method since creating dart tips can be extremely AFK and user-friendly. By using this method, you will be able to earn around 60k xp per hour which is quite decent. If you decide to go this method, remember that you must complete this Tourist Trap quest beforehand which instructs you on how to make darts.
LEVELS 35 99 Cannonballs. This is one of the most old-fashioned and well-known ways to earn money, which involve Smithing skill. In order to accomplish this you have to complete Dwarf Cannon Quest and bring Steel bars, which are necessary to make Cannonballs. Doing this method should give the player around 10k exp per hour and over 100k gold. While it's a great cash-maker at lower levels, there are better ones later on , so you should be buy OSRS GP sure you change to properly compensated ones. Experience gains that are slow are not worth the investment.