Donate.
There are lots of really good organizations that are providing humanitarian aid to Aleppo. Some of the big ones are Direct Relief, UNICEF, Doctors Without Borders, and Islamic Relief USA. all of the nonprofits listed accept online donations. There are quite a few other organizations out there that you can donate to as well. That said, before you do, do a little background research to make sure that the organization you are donating to is both legitimate and effective. As in addition to scams, there are plenty of organizations out there that mean well but have really poor execution.
Educate.
The better we understand the situation, the better equipped we are to combat it. Start by educating yourself, then those around you. While the politics of the situation can be pretty complicated and nuanced, it's important that you at least know the basics of what is going on. Share this article. Share the next one. Make sure that you are getting reliable information, and you and the people around you know what they can do to help.
Get in touch with government officials.
Even if the government doesn't always work this way, it is important to remember that the function of the government is to serve its people. Let your representatives know that you are concerned about this and that this issue is important to you. You can contact your representatives via email, phone call, writing letters, and even signing petitions. It's relatively easy to find out who your representatives are if you don't already know. A simple google search should tell you who they are and emails, office phone number, and addresses should be up on their websites.
Amplify the voices of the people who are most affected.
Make sure that all the stuff that you are reading and sharing isn't the just opinions of spectators. Watch and share interviews given by Syrian refugees and footage taken by people who are or were actually there. While it probably isn't a good idea to spam all your relatives on facebook with pictures of dead people, make sure that you are keeping the victims at the forefront of your attention, and not your own emotions.
Don't ignore it.
Don't wait for someone else to bring the topic up.I understand that there's probably a lot going on in your life right now, I really do, but the fact of the matter is that there's pretty much always going to be a lot going on. That isn't to say that turning off your phone and going camping for a few days is a bad thing, it just means that sometimes we need to make time. We cannot become so absorbed in our own worries that we turn a blind eye to all of this.
Help out in your community.
This, obviously, doesn't do anything for Aleppo and is therefore not officially on the list. However, I feel that it is important to include. The default emotion in a situation such as this is helplessness. One of the biggest things that you ca do to combat that is doing some tangible good in your own community. donate blood, organize a food drive, knit a blanket for a homeless guy. If you need to prove to yourself that there are people in the world who want to make it a better pace, go out and be one.