It is good to give through an organization. There are many organizations out there that really care about the people they serve and really give them hope. However, there are just as many organizations that see serving the needy as just a prospect for making money. Some organizations began well, but ran out of steam. Other organizations do not encourage their volunteers to be kind or loving. Don’t assume that because the organization sounds good on paper that it is good. You have to see it in action, or interview someone who has received benefits from the organization. Again, this takes time. But giving in love requires time, if nothing else.
This doesn't go against the previous tip, to give to people personally. Both are important. To give to a shelter may provide warmth to the person who you gave a nutrition bar to earlier in the day.