If you are RS gold below level 60 make sure to bring some gold coins because you'll have to pay Blast Furnace Foreman from time to time. You'll also need some stamina potions as you will run out of energy after few minutes. This technique gives amazing experience rates particularly on lower smithing levels but is quite costly.
An alternative method to the Blast Furnace which is quite expensive is crafting adamant dart hints from adamantite pubs. Level 74 is necessary to make those with a small profit. This really isn't the only benefit of using this method as making dart tips is extremely AFK friendly. While performing this method you should be able to get around 60k xp/hour that's decent. If you would like to use this route remember that you will need to finish the Tourist Trap quest beforehand which teaches you how you can make darts.
Money making methods. LEVELS 35 99 CANNONBALLS. This is one of the oldest and most known procedures of earning money that demand Smithing skill. To perform this one you need to complete Dwarf Cannon Quest and bring with you Steel bars which are required to craft Cannonballs. Doing this method should provide you around 10k exp an hour and more than 100k gold. Although it is an adequate moneymaker for lesser levels you can find better ones later on so be sure that you change to well paid ones. Slow experience gains also are not worthwhile.
Though this system gives less gain than cannonballs it supplies better expertise prices. The most important part is that you can semi AFK while generating Mithril Dart Tips so it may be a good thing to do while buy School RuneScape Gold doing other stuff on the pc.