Your timing for the sale is excellent in that any gains that are taxable will be subject to historic low capital gains rate. Unfortunately, because you have never used the property as a principal residence nor is it contiguous to your principal residence, you may not use the once every two years $500,000 Sec. 121 exclusion for gains on the sale of a principal residence.
The best way to minimize your tax hit is to maximize your cost basis. Make sure that you include along with your purchase price all non-recurring closing costs (acquisition and refi's) and improvements including permit, architechural costs, and any other pre-construction costs you have incurred.
The difference between your net sales price and your cost basis (adjusted for improvements and depreciation) is your capital gain.
Your cost basis is determined by taking your original purchase price (plus any non-recurring closing costs) and adding the cost of any improvements made during ownership and then subtracting any allowable depreciation (whether claimed or not).
Your net sales price is the contract selling price less any selling costs (i.e. broker commissions and other transaction costs as well as fix-up expenses if real property is involved).
This assumes you have held the property as a personal capital asset and intend to sell and liquidate the property. If you can document that your intentions changed from personal use to holding the property as an investment, you may qualify to use IRC Sec. 1031 to defer recognition of the gain by exchanging it with another property. Some reasons for a change of attitude can include the significance of the gain, cost of living in the area is too high, personal circumstances have changed so that you need to live somewhere else, etc.
Doing a 1031 exchange of course necessitates reinvesting all proceeds from the sale, so you will not receive any cash out in this scenario. As a general rule, to avoid taxation you have to avoid receipt of the proceeds.
For a Sec. 1031 deferred like-kind exchange you are required to use a qualified intermediary such as an exchange accomodator, qualifying trust, etc. to hold the proceeds from the sale of the land and to purchase the new property. No money must be received (or constructively received) by you during any part of both transactions. To the extent you do you will be required to recognize gain.
Sec. 1031 requires that within 45 days of the sale of you land that you identify (via letter to the exchange accomodator) your replacement property. You may identify up to 3 replacement properties whose value is not more then 200% of the value of the property sold. You must also complete the purchase of the replacement property within 180 days of the sale of the old property (or if earlier, by the due date of your return including extensions for the year in which the sale took place).
Because you have owned the property for more then one year, then the gain will be treated as a long-term gain and will be taxed up to a maximum capital gain rate of 15% (5% if the gain would otherwise be taxable in the 10% and 15% brackets). Don't forget state taxes.
Because it is impossible for me to identify and consider ALL the relevant facts, this advice is not intended or written to be used for the purpose of avoiding penalties, and cannot be used for that purpose.