Run At The Screen
Don't tell your players to run "off" a screen or to use a screen. Tell them to run at a screen.
When your teammate is trying to screen to get you open, you should run right at your teammate. Don't veer wide around the screen and give your defender a chance to ride you out. There is usually going to be some contact when you are coming off a screen, and on offense you want to force the issue. If you run around a screen or go wide, you give your opponent a lane to beat the screen.
Your mentality when you come off a screen should be to run right at your teammate who is setting the screen for you. The mindset should be to force your defender to foul you. He has to get pretty physical with you to keep you from running him into the screen, and it's likely going to be a foul. If it isn't called, you should be able to rub him into the screen and get open. Keep your hands up in the air so you don't get involved in hand fighting and get called for a push.
When your teammate is screening for you, run right at the screen. Don't widen out and give the defense any kind of angle to beat the screen. You want to be physical when you are coming off a screen. Don't allow your defender to dictate where you go. Run right at the screen, and you'll either get fouled or get open.