I know you saw a lot of people say how to make money and what not, but the thing is, you must capitalize on all of your profits you make. Here's how you can do it.
1. Go online at the server's lowest player activity,
As you know, as player activity increases, the performance of the server decreases, which affects the derivative at which the mobs are spawning. If you have any iron farms or ender farms, or potentially making a guardian grinder, go to online at the lowest peak, and sell all of your things. plan and simple.
2. Sell your things in v-shop.
There's going to be people that will be willing to by your items. Just list them at a reasonable price, instead of putting your items on sale for a ridiculous amounts of money. That way, people can eat up all the items in which you are selling!
3. Stay at your grinder for as long as possible.
Obviously, everyone here has work or school to attend. But, if you want all the monies, you have to stay in the grinder for as long as possible. If you're a hunter, it will benefit you significantly as you can make hundreds of thousands of dollars in hour (Please don't use a blaze grinder as it is super inefficient!)
That's all. GET THEM STONKS™