If you are pocket passer, you should practice working in the pocket. So many times, I see a guy hike the ball and then back straight up. In my experience this allows the DEs to break free and come after you quicker. When you hike the ball just stay in the pocket and make small movements. It is amazing what routes open up. When you keep backing up the ball has further to travel and give the defender more time to get to the WR. You do have to watch for pressure up the middle sometimes, but just be patient. If you get a little pressure just try to move away with small movements. At first you kind of feel like you are going to get swallow up, but as you get more experience it isn't a big deal.
Another thing I can tell you is practice throwing the ball away (make sure to be out of the pocket). There is nothing wrong with throwing the ball away and living to see another day. Worse thing you can do is try and force a pass and it get picked off or you get hit and fumble the ball.
Last but not least. Sometimes you just have to take the sack. Don't I repeat DON"T force the ball. It is alright if you get sacked. Yeah it sucks, but at least you still have the ball (in most cases). I think that throwing the ball away or taking a sack is a lot better than throwing a pick and having them down on your side of the field.
These may seem like small things, but they are important and can make a big difference. A lot of times the small things are what can make you a great player. I am sure people will disagree on some. Some people may use a mobile qb, but for a pocket passer this has worked good for me. I was in the same boat as you. Another thing is get really comfortable with you offensive playbook. Like other said. Try to read the defense and adjust accordingly. Take your time. Don't rush your plays.