Video games tell you what to do using quests or missions. There's no reason this can't work in real life, too. Books tell us to lead purpose-driven lives with long-term and short-term goals. Seems like a perfect way to make your life an RPG.
A mission is an achievable goal within 3 months or less. A mission should be broken down into sub-tasks. In other words, it's an actionable short-term goal.
I prefix each mission with a projected date of completion (
1702 is 2017, February), but this is totally up to you. I do this to get a good retrospective at the end of the year of all the missions I've completed.
This system is so simple, you can use anything to keep track of it. As an Android user, I prefer using Google Keep. It lets me view all my missions at a glance, both ongoing and completed.
There are a variety of other ways to keep track of your missions, including using plain notebooks and pens. What's important is you break your goals into manageable pieces, and give yourself a way to look back on your progress.