This is a great post O.P, and a timely reminder to do for others. These are some things I've found to be helpful. Just for reference, I'm in my 30's and female. I only mention it because some people feel more comfortable accepting help in certain situations if you're female. No offense to guys meant, loving the gentlemen, that's just the way society is.
On that topic, if you switch brands or have unused products for some reason, please consider donating such to a women's shelter. They can really use them. Lots of people give food etc, which is very kind, but forget that a woman on the street spends almost a week of every month bleeding.
Keep your eye on your elderly neighbours in terms of their safety and well being, and take time to talk with them. Even if it's just when you take the garbage out. Make an effort. A lot of the elderly are desperate for company. We have elderly neighbours and I always make way too much food - big pots of soup/stew/pasta or whatever - I end up having to discard at least one good sized portion. Now I pack it up and pass it on. Sit and chat for a bit. Your elders are amazing, and have the best stories ever. It's criminal how ignored and under appreciated they are.
Do something nice for your refuse/garbage collectors. In my neighbourhood it's traditional to give them a cash 'thank you' for Christmas. You could do want you want though, they're coming to your house anyway. Old but serviceable clothes, some food, maybe just a card saying 'I appreciate the hard work that your team does. Thank you.' We had a strike by the refuse collectors, it was city wide, and let me tell you, I appreciated very quickly what they do and how important it is. It's a stinky, hot, physically intensive job. A sincere 'thank you' goes a long way.
Tip as much as you can afford. People rely on that money and sometimes (especially in food service) people have a bad day. Also, lots of problems stem from the kitchen or the management - it's not the waiter's fault, but it ends up being their fault because they're on the receiving end. Try to be understanding and kind.
Register to become an organ donor. It's free, quick and easy. You can do it online, it's just a quick Google. You even get a bracelet/rubber band thing (I haven't applied for mine yet). You can save 7 lives just by doing that. I'm thrilled that I signed up (my country has a 0.7% sign up rate compared to America's 30%). Read all the information that they give you, it answers a lot of concerns. They will not let you die because you're an organ donor. In fact, if you are an organ donor, it takes 3 doctors to independently declare you dead and make a decision to harvest your organs. You're actually getting more 'am I dead?' attention than NOT being an organ donor, simply because of the legalities involved.
Always give up your seat or space in a line to an elderly/sick/pregnant person. That should be a no brainer. If you can see that a line is long, and that someone is in discomfort, go to the store assistant/manager and request a wheelchair. Many stores have them, you just have to ask. Push said chair and help the person to their next destination by helping them load groceries etc. For some people, doing even simple tasks is agonising. Be grateful that you have your health, and help those who don't.
Keep an eye out for the kids in your neighbourhood. If a kid keeps pitching up and talking to you for no apparent reason, there's a reason for that. Lots of kids are trying to get away from a difficult home situation and will latch onto any form of support, particularly from men who can show them how an engine works, how the computer works, how to plant gardenias. Do this, and mentor and love a child who might need that desperately. Don't ever take advantage of said need in any way.
Pick up litter wherever you see it. A clean environment makes everyone in your neighbourhood feel better.
If your neighbour's pet gets run over, and you happen to see it, dispose of said animal in a quick and respectable way. It's up to you whether or not you tell them. Personally, I'd just go with 'no, I haven't seen him/her.' Sometimes the truth is overrated. That may seem dishonest, but often, especially if the pet is very loved, it's kinder than 'yeah, I scraped them up off the pavement because some jerk ran over them.' A person should know when to use their words. To me at least, that is not one of those times.
If a person comes to your door asking for food, give it and give gladly if you have the food to spare. Remember the scripture - 'You who entertain beggars - be aware! You may be entertaining angels.' I was broke the other day and all I had to spare was a butternut and a box of soya mince that would make 8 servings. Guy couldn't feed his kids, and he was overjoyed. Those were my 'emergency rations'. I'm glad that food helped him out of a true emergency. Be kind.
That's all I have to say about that.