Also, my big two rules when it comes to charitable giving:
1) go to guidestar and make sure the charity you're donating to is using the money effectively. It changes from sector to sector, but generally no more than 14% of their overall budget should be spent on marketing and admin costs. If they are spending less than 86% of the money they receive on these non-program costs, it's not a good sign.
2) Give your money or your time. Generally speaking, the non-profits I've worked with have a shortage of labor (especially skilled/semi-skilled) and would like your time more than anything. If not, money is a close second. An example with the food bank: they appreciate your food, but when you give food they have to sort it and store it. If you give them money: not only can they buy the specific products that they need, nutritionally, but they generally have more buying power than the average consumer so they can actually buy more/$ than the average.
Not to say that they won't be grateful for any donation, because they will.
