Tack Attack
The smaller the target, the better the strike. Stick two pieces of tack on the putter face, just wide enough to strike the ball cleanly. This practice will lessen your misses and ensure consistent speed.
The Ruler Drill
If your start line isn't as consistent as it could be, try rolling the first foot of the putt on a ruler -- it'll get you straightened out in no time!
Watch The Dot
Peeking early? Try drawing a dot on the top of your golf ball and focusing on it even after the ball has left the club face. You'll be back to striking it pure in no time.
Ball Lines
Experiment with pen lines on the golf ball, try one parallel with the putter face, one perpendicular to the putter face, and even both. The key here is seeing which works best for you.
The Coin drill
Place a coin just behind your ball at address and ensure you're stroking just a little bit on the up through impact. It'll get your ball hugging the ground quicker and sticking to its line better.
The One-Hander
To resolve a 'push', try making putting strokes independently with your right hand only. It'll heighten the feeling of the club face opening and closing, and negate the dreaded quick jab outwards.