Put on some extra deodorant, crank up the AC if you're driving, arrive early so you're not sweating in a mad dash, and then wow them with all you've got. I'm rooting for your success.
When I hear from people who've been out of work for six months or longer, they often say they've tried "everything" but "nothing" works to help them get hired. If that describes how you're feeling, try starting over. By that I mean revisit some of the tactics and people that you tried previously but didn't pan out. For example:
Check out your public library to see if programs and services for job seekers are offered.
Reconnect with 25 people who you initially spoke with about your search to see how they're doing and to inquire about any new leads they may have.
If you got close to an opportunity but the company chose someone else, touch base with your contact to reiterate your interest in the organization.
Limit your reliance on applying exclusively via big job boards.
After submitting your resume for a position, go find a person who works at that company with whom you can talk directly about the opening.