Depends where you live. You can usually find people you know who would appreciate. I personally don't give clothes away in bulk, just give them to the individuals around you who are obviously in need and will use them. I don't trust any organization not to pick and choose and sell and take for themselves. I give quite a lot of stuff away to people I know who work damn hard and get paid very little. The boys at the Colmado who are there 24 hours and day, sleep on the floor at night when the shutters go down, and then are up and working as soon as the shutters go up every morning with every other weekend off to visit the family in Campo with their 15,000 p/m salary, seem to deserve the odd used pair of Adidas or tracksuit I've outlived for myself.
There is always the old people who haven't had an income since hubby or the wife died and are to old to work, always on the beg, it's nice to give to them and if they sell them it doesn't matter, they truly are in a situation and could do with it. I know there is a lot of work goes out to the orphaned kids around, but I often feel the older generation are forgotten about and they to a great extent are in some circumstances more vulnerable than the kids as they seem to be unnoticed, I try to help the oldies when I can.
I stopped giving away in bulk when I went to Africa and saw that a very large international charity which millions give to in good faith were actually selling the clothes to the people of poverty who obviously don't have any money which defeats the object, and I am certain of that people donating are unaware of.
Make it personal, it feels good to see someone so sad smile.