Working with weights should have purpose and focus, regardless of your goals, and at the heart of that purpose should be the isolation and exercise of specific muscle(s).
The video above shows how to lift a weighted bar to so isolate the upper part of your chest in a safe and effective way.
The chest muscles, typically, are made up of one large muscle group. As such, how the bench is positioned, and where it lands on the chest are both crucial issues.
As demonstrated in the video here the barbell will touch (gently) somewhere above your sternum.
The pace of the bar lift in this demonstration is steady, with a slow drop down in order to localise the muscle group being targeted in the exercise routine.
When lifting during the routine count for 3 seconds on the way down and then for 3 seconds on the way up (which, as a timing tip can work for most exercises similar to this).
Of course when adding weight to the bar, you might like to increase the speed of your motion, and you can do this if it takes place in a controlled and safe manner.
Finally, when lifting in this way try to remember that you train to burn calories, to gain muscle definition and to become stronger, but you will not achieve any of these objectives if you exercise using the wrong form.
So maintain a clean and focused technique at all times!
Julien