As the previous post said, there are genetic differences; you don't have to have that exact look you're interested in to be lookin good, Everyone has different pluses and minuses so don't worry too much about the look of others. Funny thing about it sometimes you'll find out that someone who looks better wishes they had something they can't get too.
On the other hand, as much as you can bring out what's there it's good to try different things. I agree with the post about bringing out the lateral head to make the bis look bigger from the front. Best exercise i've found for that is dip machine, wide-elbow pushdowns, bench dips. Some like close-grip bench for that. Standard pushdowns are one of the least effective IMO, even though they're widely done.