My take:
Gay Marriage: The ship has sailed. The majority public perception of gays used to be they were a small but hardcore group of aggressively flamboyant, assless chaps wearing (yes, I know it's an oxymoron) men who going out of their way to be offensive and completely dismissive of public decency and decorum. Now gays are generally perceived as civil, suburban, child adopting, and proponents of typical middle class values and habits. Easy to oppose gay marriage when they're scaring your children at the gay pride parade, hard to oppose when you see images of loving, professional, respectful couples that look like neighbors (the neighbor who makes you feel embarassed because they upkeep their house better than you).
Hispanic: Need to change focus from "stop t3h Mexicans" to "We have rules for immigration and you need to follow them." Press for a compromise that allows "undocumented" workers to admit they broke the law and pay a decently-sized fine in return for a work permit. No citizenship pathway until all those currently in the legal immigration queue is cleared.
Economics: Opposing open-ended welfare isn't enough. People don't like seeing multiple generations on the public dole, but you need to have an alternative solution that works better since the public isn't ready to throw them to the wolves either.
Abortion: GOP is mostly right on the merits, but with no clear resolution in sight this is a battle best left unfought. Sure it motivates the hardcore partisan troops, but the larger public is tired of arguing about it and wants the issue out of sight for now. Medical advances are constantly working in the favor of the pro-life side as the age of viability gets pushed earlier and earlier, let this work quietly in the background for a while.