I use lip primer, foundation then powder. I generally use liner just around the edges. That should prevent feathering.
To keep lipstick off your teeth try this: Form an O with your mouth around your finger, and gently slide your finger straight out of your mouth. Any lip colour that was on your inner lips is now on your finger. This step is crucial, as lip colours on the inner lips will rub off onto teeth after you've left the mirror.