Just keep sight of your goal and be honest with yourself on your strengths and weaknesses. I know it may sound stupid but you have to capitalize on your assets and sell yourself. Unfortunately in most interviews you do not get much time to do this and without some experience/planning you can miss the window to show them why they should hire you instead of the other 10 qualified applicants. I did not get hired at the first place I interviewed at and looking back I don't blame them. I was a way too nervous and never got comfortable enough to make a good impression with the HR staff. But all worked out for the best in the long run and I ended up with a better job IMO.

So keep after it and use the experience to make you better next time.