Negotiate fair prices for goods and services. This goes both ways: Don't haggle just so you can tell your friends that you bought a trinket for a penny, and don't pay $10 for a cab ride that should cost $1 just because it seems like too low a price. When tourists overpay for basic services, it changes the economy and locals can't afford them anymore.
Don't give handouts, especially to children. Unfortunately, children are often pulled out of school to beg, and giving them money directly will only make it more likely to continue in the future. If you want to give money to help the individuals you meet while traveling, consider making a donation to a trustworthy nongovernmental organization or charity in the community.
As for your upcoming trip, unfortunately all-inclusive resorts are probably the least likely to follow responsible tourism guidelines. Most of the money you pay probably bypasses the local economy and goes to an overseas conglomerate. The food is probably shipped in. And the higher-paid employees may not even be locals.
But if you decide to go anyway, don't just throw up your hands. Do what you can to follow the tenets and ask the resort what its practices are. Does it buy food from local farmers? Does it pay employees a living wage? Does it have a policy aimed at minimizing its environmental impact? Tell them that these things are important to you as a consumer. That way you can try to make sure your vacation has a positive impact—on both you and those you're visiting.
Do you have a real-life do-gooding dilemma? Please send it to firstname.lastname@example.org Sandy will try to answer it.