Let's say you were creating a new superhero and you wanted that superhero to have a shield. What would you do to try to avoid any automatic comparisons with Captain America? It appears to me that pretty much all of the other shield-bearing superheroes out there are Captain America clones of some kind, but I'm wondering if merely not having a patriotic outfit is enough...

Having him NEVER throw the shield is a good start. Having the shield not be circular is another step.

If the character has a theme that lends itself to shield use, like a knife or African warrior, all the better.

I would agree that never throwing the shield would be a good idea... one of the things that came out of Rob Liefeld's Agent America/Fighting American litigation with Marvel was that he could never depict his character throwing his shield.

I'd give him wings

I think Hawkman having a sword as well helps-- the sword and shield combo is a classic one.

Call him Legionary and have him come from Italy.

Call him Tampax.

I'm not talking about a sword and shield... just a shield.

Does it have to be a solid shield? Could it be an energy field, like a force field?

Have it be crystaline and semi-transparent. Diffuses lasers into harmless light, reflects sonic attacks, regrows and reforms if shattered, provides telescopic/infra-red vision if looked through, creates blinding "flash-fields" to stun/disorient opponents, etc. Hope that helps.

Have him wear it on a different arm

Have it fit on his back under a jacket... oh.