This is a great chest exercise for hypertrophy if you have good motor control. Start with the incline bench set at about 45 degrees, higher than you would normally use for incline bench presses or flyes.
With a slight bend in the elbows, initiate the movement by contracting your pecs. Really try to "open up" the chest.
Don't bring the dumbbells straight down; that will just hit your shoulders. Notice the natural arcing motion of the arms. The dumbbells start at the sides and should stop above the upper chest.
Newbies often waste their first year or two of training. They should be taking advantage of this magical time. Here's what to avoid and what to do instead.
Besides meaty arms, the pectorals are probably the best of the "showy" body parts. Somewhere in time (oddly enough at the same time as the rise of Arnold Schwarzenegger), the chest became the ultimate sign of manhood. Thick pecs give a three dimensional look to the upper body, and a well-defined chest makes your torso look like an old Roman soldier's breastplate.