Well, the first chord of each triplet is accented, so break the passage up into threes, so that you're only practising one triplet. Now, play the first chord of the triplet very loudly and the other two as softly as possible. Repeat this so that you get the feeling of the triplet figuration. Then move to the next triplet section and do the same, as it is the Left Hand that has the accent this time. Once you get the feel of both of them, you should be able to accent the triplets correctly.