Investors & landlords

I'm sorry. I have trouble grasping the concept of "annualized method".  Since my income varied from period to period, do I add the actual income for each period?  If not, how do I calculate the income for each period?  If I add my annual year and dividend by 4, wouldn't that make my income spread equally over the 4 periods and I lose the penalty reduction since the capital gain was in 4th quart and is by far the largest item of my taxable income?  

 

Thanks.