You will get this after the This Kid's Got Potential
achievement and before the Talent Show
achievement. By the time you get close to finishing 3 Talent Trees you should be very familiar with how they work and what you're doing. If you want to get this achievement fast then focus on one Talent Tree at a time. I suggest, however, to just purchase the Talents you want and let this achievement come with time. For the Talent Show
achievement you will need to purchase ALL
of the Talents anyway, so you might as well just let this one come naturally.