Do not replace the fuse with a larger one - EVER!
Obviously you either have a short in the fuel pump circuit. It's surely a short in the wring, a bad fuel pump "controller" (whatever they call it) , or a bad fuel pump.
Id:
1) Disconnect the fuel pump at the tanks and see if the fuse blows. Gut tells me the pump is most suspect. One reason to start here. If not the
2) Disconnect the pump controller (inside rear passenger side "fender") and see if the fuse blows.
3) If it still blows, then the issue is the wiring between the fuse controller.
Everything behind the each test is probably good if you've never oversized the fuse and it still blows.
If you have oversized the fuse, then the harness warrant more suspicion . . .
Honestly if you have to ask how to trouble shoot it here you are going to have a tough time. Did you get it home? When do you need it running?