Generally if you had 1040-ES vouchers generated on your prior year tax return, you'd likely want to make those estimated tax payments quarterly. However, you can avoid penalties on your current year tax return if you meet the following criteria:
Your filed tax return shows you owe less than $1,000or
You paid at least 90% of the tax shown on the return for the taxable year or 100% of the tax shown on the return for the prior year, whichever amount is less.
Ruth gave top notch advice, but as an add on. Please don't forget estimated taxes should be calculated on all sources of income not just self employment income.