If the concern with illegal immigration is more of the
"dey tuk der derbs" variety, wouldn't E-verify, and proper enforcement of it, solve a lot of problems? I also think allowing a lot more legal immigration (not just guest workers, we need to make a choice whether we want cheap food grown in the United States) for farm workers should be allowed, since America is in a huge need of such workers. On the other hand, you can clamp down on illegals working in construction or flipping burgers since Americans are more willing to work those jobs.
I think more strategic fencing would be great, along with more drones patrolling the border perhaps. In terms of Visa fraud, if we enforce E-verify, that problem would solve itself as well. Institute a DREAM act so children can become citizens sooner, and enforce a long probationary period so the Republicans are satisfied that they are really, really assimilated before they start voting. Also, I would allow more streamlining of H1B visas so we can get more younger, well paid immigrants who can help with the coming entitlement spending.