Well first you should take a look at how you are holding the pick. And relax yourself. Get a firm steady grip on it. And though it might strain you to keep that while skipping strings practice slowly at it like that. Get used to it. Eventually it will become quite easy to slice through the strings at blazing speed with amazing accuracy.
Next take a look at where you are palm muting. There are some sweet spots near the bridge. And some not so sweet spots further away over the bridge pickup. Your task is to find the right tone for you. Whether you want it to be especially heavy closer to the bridge or especially tinney and dead further away. Don't get too close to the bridge or you might just end up muting the strings completely. Seek out that sweet muted spot.
Lastly work on your alternate picking to bring every stroke under complete control. Let no movement be in excess as you will waste time and energy having to compensate for excess movement on your part. Speed and accuracy are a byproduct of coordination.
Also learn to play from the wrist good. No crazy arm movements. Though some forearm movement is acceptable and not at all unwarrented in string skips n such as you must position the hand better to continue picking. I am going to repeat the most obvious thing you should do reguardless of what you can do on the guitar. Practice slow. Build the speed. Build the power and control.
From there have fun.