This is one of my favorite topics.
A few things that I currently follow: it matters less how you make your money, and it more matters how you spend your money. Everyone needs a job and savings and a retirement plan, and we do what we do to make money based on what other people are willing to pay us to do. If the job pays well, someone will do it.
It's your spending that does good or ill. There are a few things I do on this front. Firstly, I believe in iterative wisdom. So, if I figure out something I think is 'good' to do, and I'm wrong, I do something else. If I donate to a charity, and find a better charity, I donate to the new charity instead.
I also believe in just giving. I read somewhere that if we were to focus 2.5% of GDP on fixing some of the world's problems, those problems would get onto the trendline where we're fixing them. I earmark 5 hour's wages per month to the various causes I believe in that I think 'make the world better in the long run'. Sure, this is about 3%, but I'm covering for slacktivists who like posts and do nothing else.
There's also a certain pleasure in asceticism. There are some types of spending that nearly 3 billion people cannot do, because of poverty. If said activity is destructive, I try to refrain from doing it. I am blessed with my luck, but this doesn't mean that I have permission to do things that others cannot. I should be using my wealth for other things. If I realize that they're happy, then maybe I can be happy too. Don't borrow, because then you're giving your money to the bankers. If you don't borrow, you're giving more of your money to people who work for a living. In Canada, this means I am using debit instead of credit, even.
Also, I try to avoid activities that it's best if 3 billion other people not do it.The world is hooped if 3 billion people eat a lot more meat, so maybe I shouldn't be on the 'team' that's ruining things. Heating my house too much. A fancy, expensive car.
Something I realized: lots of us tip generously. So, we're try to be generous. We like it. After that, it's a question of where you're spending your generosity.
It all starts small. One year for New Years, I decided to no longer 'walk past' a gloveless panhandler in the winter. I suffered from that paternalistic 'oh, they'll spend the money on booze' that lots of people fall for. So, I bought new gloves and had them in my pocket. If the panhandler was gloveless, I gave them gloves. It didn't fix their lives, but I think that 'pain mitigation' is an important thing.
I now carry bus tickets. Whenever someone asks for change for the bus, I give them a ticket. If a person needs a bus ticket, I am always happy to give them one. If they want to sell it to someone else who needs a subsidized bus-ride, whatever. I am happy to have them help me find someone.
But 'needing less' is important. Shifting your spending so that you're not buying destructive things is important. Spending less on exotic vacations is important. Eating way less meat is important.
Edit: the trick is to double-punch. Don't just limit your harm, help make the world better. Polio. SETI, Food Bank, it doesn't matter. It's the building that improves things.