yes, grow it giving it the best care and the optimal conditions. There's no one sure fire way to increase the thc percentage inherent in any said strain...sorry if I can't give you a simple b/w answer because there is no true answer to that...
There is, grow the strain out several times, learning it's every need and characteristic. When you have it down pat, you're likely to have increased THC% (over previous grows) as well as taste and yield!
:yeahthat: that's gonna be the very best method for maximising your yeild and potency. But you also have to be willing to try different things each grow to see what improves it. However, Don't try to change up things during the grow as that will confuse your learning and can stress the plants.