Keeping track of my business

My business is an LLC, am working on getting dealers license at this point, plan to buy wrecked/repair/sell.

I am trying to do everything 100% legit as mentioned in above post and within reason ( my reason ) I am there.

I am trying to learn all of the loopholes that the big business take so that I can show no income or little to none and still make a decent living.

Thanks for all the input, it is a big help.