A huge mistake by a lot of business owners is to blow through their income and not sock anything away for taxes. That hurts a lot of small businesses during the first year they are in operation because their owners don't really think so much about taxes.
Some advice? Set about 25 percent of your income aside during that first year to be sure you will be able to meet your tax burden and then rely on withholding estimated taxes after that.
One of the great things about estimated taxes is they effectively force business owners to consider their tax burdens and keep enough money on hand to meet them. The first year in business can be rough, but estimated taxes make it easier to manage money so enough is left over for the government.