Because they don’t drop below 2200 for a long time since they have an average alch of 2380,, you can purchase them at 2200-2250 and sell them for 2300-2350. This isn’t the fastest method but it’s consistent. for those who are members you are able to purchase more exotic items such as black chaps RS Gold, which you can purchase at 5400 and selling for more than 6000, but if you don’t time it right, you could end up with stocks for a long time.
Beware of red dragonhide as it is not a good seller and you should avoid seeds as they’re a scourge, I’ve lost a fortune from these seeds. The method is to look up the graph for 180 days and observe what bounces frequently between two points. You can purchase and sell before they get to them. It takes some time but over time it’s possible to earn huge profits of between 1-2 million everyday…do woodcutting or slaying simultaneously so you don’t waste time either.
Herb running (in the sense of) is the process of running between the various herb patches in the most efficient method. It takes a while to master the proper route from the one that is in the swamp (forget that name) and the one near draynor manor and the one to the north of Ardy, the one in Catherby and (if the quest is completed) the patch in Trollheim.
The aim is planting (usually) one of the highest-profitable seed of the herb which will yield the highest profits when it is harvested. I’m not sure of the ideal level at which to begin or even the current price Old School RuneScape Gold. But, I wouldn’t recommend you to start with your current level until you have access to additional herb options.