I am so frustrated right now.

Your sentence is fine, but changing it to "right now" makes it feel more natural.

Because I am doingI have an independent business, and I had a bigto sell an important item to make money yesterday.

It's better not to start sentences with "because". You can get rid of it here.

Your sentence isn't that clear either, so "I had a big item to make money" is confusing. Do you mean you need to sell this item to make money? I corrected it, but I'm not sure if it's right.

But, I coulHowever, I didn't get a lot ofs much money as I expected.

On top of that, my acquaintance made a lot of money by selling the same item.

I heard thatthink I have to make an effort harder effort, but I want a change of pace.

What do you mean by "I heard" - who told you this, where did you hear this? Maybe you should write "I think"?

Also, the phrase is "make a harder effort", or you can say "work harder"!

I want somebody to let me know how I should I do this.