6.给大脑充充电。“过载的大脑需要休息，才能优化运转，”赛尔克表说。“大脑真的很像一块电池，只要一整晚的睡眠就可以充好电。”连续几天努力工作，人困马乏？没问题，只要你能每隔几天就好好地睡上一晚上八小时。

    “白天脑力放松也很重要，”赛尔克说。“拿出日历，未来三周每七天安排一天休息。你会发现另外六天自己会更有效率，精神上也没那么疲惫。”

    为什么要花21天时间来做这些？因为最新的大脑可塑性神经病学研究显示，用一个新习惯取代旧习惯需要21天。当然，为了方便计算时间，也可以考虑坚持整整30天。其它的新年愿望也可以这样。

    高管教练兼作家罗瑞·瓦登委托研究公司Kelton对新年决心进行调查时，结果很有意思。2012年，每两个美国人里就有一个立下了新年决心，可以预料到的是，近半数人（48%）在某个时候就半途而废了。很多人1月份还没结束就已经选择了放弃。但在那些坚持了30天或更长时间的人中，有超过3/4的人（76%）在调查时仍然在坚持履行自己的新年决心。

    “要靠自律做出真正的改变很难，”《通往成功的七级台阶》（Take the Stairs: 7 Steps to Achieving True Success)一书的作者瓦登说。“但如果我们能坚持到第一个月底，我们做出长期改变的可能性就会增加3倍多。”

    6. Recharge your mental battery. "The overloaded brain needs rest in order to function optimally," Selk notes. "The brain really is like a battery, and it only needs one full night's sleep in order to recharge." It's okay to work hard and be mentally tired, even several days in a row, as long as you get one solid night of eight hours of sleep every few days.

    "Mental rest during the day is also important," Selk adds. "Take out your calendar and schedule one day of rest for each seven-day cycle for the next three weeks. You will find yourself more productive and less mentally exhausted during the other six days."

    The reason for doing all this for 21 days is that, according to recent neurological research on brain plasticity, that's how long it takes to replace old habits with new ones. Just for good measure, though, you might think about keeping up these behaviors -- or any other New Year's resolution you've made -- for a full 30 days instead.

    When executive coach and author Rory Vaden commissioned research firm Kelton to do a survey on New Year's resolutions, the results were intriguing. One in two Americans made a resolution in 2012 and, predictably, nearly half (48%) of those quit trying, at some point, to keep it. Many gave up before January ended. But among those who persevered for 30 days or longer, more than three quarters (76%) were still sticking to their resolutions.

    "It's tough to cultivate the self-discipline to make real change," says Vaden, author of Take the Stairs: 7 Steps to Achieving True Success. "But if we can just make it through the first month, we're three times more likely to make a permanent change."