This is such a tricky subject and because of that I have a CPA that helps me with all of these types of questions and if you own real estate of any sort I would highly recommend you find a good one and pay them what their asking. If you need a recommendation for a great CPA, I can refer you.
Otherwise, or in the mean time I would refer you here to get a solid understanding of capital gains as a whole, what it is, how it works, what it applies to and when you may have to pay it.