Here’s my one piece of advice about personal organization: (calendars, tasks, planning, tracking): Think hard about your needs, pick a system, and then do not under any circumstances change it until at least one full year has passed. When you discover that your chosen system has some flaw — which you will — you’ll be tempted to change to a different system that doesn’t have that particular flaw. But: the new system will have other flaws, because no system is perfect, and those may be worse than the one you’re dealing with now. And you can lose vast tracts of time trying to find the (inevitably nonexistent) perfect system, which will make it harder, not easier, for you to get things done.
Moreover, you’ll need several months, at a minimum, to fine-tune whatever system you’re using to meet your needs. You won’t really know its weaknesses, or its strengths, until then. After a year, even if you’re frustrated by some things, you’ll be using it well, and can make a rational decision about whether to exchange it for something else. But remember: should you change, it’ll take you a long time to learn your new system. Are you sure you want to invest that time?
Some people are sure. And there can be value in shaking up your familiar habits — I do that myself sometimes. But the better you know a system, the more accurately you can calculate the costs and benefits of abandoning it.