Being nice is an important skill that everyone should be proficient in and practice every day. Here are some small, low effort things you can do to hone this skill while making the people around you happier:

Hold the door
-In some places this is very common for people, however I have not noticed this much up here. Don’t worry, you won’t look weird if you stop for a minute to hold the door for the person behind you.
-It is especially nice to hold the door for someone in crutches/with a walking stick/ in a wheelchair if you are near a door.
-You don’t have to hold the door for too long, if there is a pause in people and you need to go people will understand.
Smile
-It is a great way to start getting to know people. Smiling makes you feel better too. If you pass by someone and smile often enough, you might also start to make small talk and you might even get a new friend.
Say please and thank you
-It’s just polite, please do it.
Compliment people (genuinely)
-If someone looks good with their new haircut or their shirt has a cool band you like on it, don’t be afraid to compliment them, it could make their day.
-Don’t try too hard to compliment someone or say something you don’t mean.
Random Reminders
-If you don’t have something nice to say, you don’t have to say anything.
-Don’t be too nice such that people take advantage of you.
-You should not be drained by being nice, be able to set boundaries.
-Treat others the way you would like to be treated.