It's a great feeling, isn't it? Checking something off your to-do list. Mission accomplished. Done. But it's also easy to let that list grow to herculean proportions or have a whole day (or week) go by without checking anything off your growing list of tasks. How does this tool for getting things done become a stack of ticking time bombs, flaunting your procrastination? It all comes down to your planning and how you write it. Here are the seven tips for mastering your to-do list like a boss.