If your MiFi is (USB) tethered to a PC then there is no WiFi troubleshooting to worry about. All you need to do is provide the best possible reception that you can from VZW to the Jetpack. This may require you to explore your environment a little as the current location may not be optimal.
This process of exploring a space for the best reception is called a "Site Survey". By systematically testing each location in an area you will plot out the spots that work well and those that don't.
To do this you need a few things:
- Access to the MiFis signal strength indicator
- A website like speedtest.net
Move around and check these two variables. Plot the differences and record where the numbers are the highest. What you should see is that the areas with the best Line of Sight to the local tower with the least amount of interference/stuff in the way will perform the best.
At that point you will have seen the best case scenario. Its then up to you to explore options to pass along or improve that reception to the areas that you want it in. You can do that a number of different ways such as setting up a Verizon Network Extender or a 3rd party cellular booster/antenna combo.