Static holds, pauses, isometrics... whatever you want to call them, are an essential part of any athlete's programme. The problem is, no one does them!
Well, they're disgusting, I guess, and nobody likes to step past that comfort zone. The problem is is that the lack of isometrics in your programme might be what is holding you back.
During the early stages of a lifter's development, exercise selection is easy. Once you have identified an area of weakness (whether that be physical weakness or technical), you can simply break that movement down and isolate that portion of the movement. Prioritising the improvement of that part of the puzzle by spending more time there will certainly help, but nothing works better than isometrics.
A common problem is that lifters allow their hips to rise early in the first pull, thus resulting in the chest to fall and they then pull with their back. Try placing more weight on the bar than what you can pull, set up correctly using the check-list below, and push the ground away from you... hard! It's going to hurt, a lot, but it'll be worth it I assure you.
Weight distributed slightly in front of the mid-foot
Knees in front of the bar
Hips slightly higher than the knees
Back flat, better still, arched and tight
Shoulders directly above the bar
Shoulders internally rotated so that the elbows point upwards
Ensure that your position does not change, at all, when you initiate the static pull. You should feel it in your quads and little anywhere else. If you do, theres a good chance that your set up is wrong. Continue to pull (push the floor away from you) as hard as you possibly can for at least 10 seconds.
You'll hate me now, but you'll thank me in a few weeks!
Try it and let me know what you think :-)