How do i lose fat on my chest ?

I'm 16, 5'8" 155 pounds, i've been doing p90x for about a month now, and for the first time i'm able to feel and somewhat see my abs. before i started p90x, i was running every night for about 2 months at least 45 minutes every night. this didn't seem to help me lose much fat even though i've been eating fairly well (not eating quite enough). p90x has done wonders for me so far except my pecs, i can never seem to get a good chest workout. although i can feel the pecs and i can flex them, there's still a good sized layer of fat on top of them, i wanted to know what my best bet for getting rid of fat is (mostly on my chest but also on my stomach)? i'm not going to stop p90x but what i am looking for is mostly guidelines on my diet, and additional chest workouts that i can do, if you have any suggestions that would be great ! Thanks.