Guides to Merching?

Well in a 1 day trend you can tell if the prior day it had been purchased a lot if the price went up.
Chances are if on the 3 month trend if the price was going up gradually then it's a good investment.
If over 3 months the price went up slowly but in the past day it went down slightly then it's a low risk
Investment. Like if grimy guams are 3 gold each 3 months ago and went up to 12 gold currently but went down 2 gold the day before
I'd invest buying there as a low risk. Because if you buy up the stock then the price will continue to rise slowly meaning you'll risk
Very little and profit very little. If the curves over 3 months are more extreme the risk goes up. As an experienced player you know
Key items that have been traded and are being traded as necessities. Examples are herbs to make overloads. Those generally are a
Lower risk because there's always a buyer and a seller.

Last time I tried to learn I was shown with Oak Planks, is it still pretty much like that what your explaining with the most traded items? I don't have a ton of money, and like I said I do make a decent amount, but it's made slowly. I did invest in some stuff to make that I bought cheap and the finished item is worth more, which I don't mind doing as it helps XP gain, but I don't always want to do that since it's a much slower way to gain money.

How do you know when it's the right time to sell? Do you wait a few days after you buy, or do you just dump them back in GE but at a higher sell price and wait?