From Quora: My Answer to "What is the best advice for a sophomore, like PSAT and college advice?"

Start studying for the SAT and ACT. SAT study will also prepare you for the PSAT, which is a watered-down version of the SAT. Try the Barron’s SAT Premium Study Guide, which is the 30th edition of Barron’s SAT. The 28th or 29th edition would also do. The ACT’s official study guide would work for ACT prep, as would the Manhattan Prep 5-lb Book of ACT Problems. You should also use the Khan Academy SAT prep materials SAT | Test prep | Khan Academy (they’re good, they’re free, and they’re the official SAT prep materials recommended by the College Board, the maker of the SAT), as well as the free SAT practice tests you can download from the College Board website. SAT Practice Tests


You can use my free YouTube channel for more help with SAT, ACT, and other standardized test prep: John Linneball Tutoring


Seriously consider what you’d like to do for a living. Law? Politics? Medicine? Engineering? Fashion? Entertainment? Anything is possible, but it’s best to look for a career that appeals to your academic, personality, and social strengths, and which also appeal to your interests. Ask yourself what you’d do for very little money and still be happy. Then look for careers that let you do that thing. Start looking into what colleges are good places to get training for the kind of career you want.
​

Hope this helps!