Neil Pasricha, NY Times Bestselling Author of "The Happiness Equation" & "The Book of Awesome", wrote last week:

The good news is you only have to do one not all five.

My suggestion is to pick just one from the list below and set a 20-minute recurring reminder in your calendar for 20 days in a row. See if you can develop a new 'happiness habit' : 

1. Brisk 20-minute walk. Studies show three 20-30 minute walks a week outperform, from a happiness perspective, test groups on anti-depressants and test groups doing both the walking and taking the anti-depressants. (Penn State / Babyak, American Psychosomatic Society)
2. The 20-Minute Replay. Journal for 20 minutes about a positive experience you had during the day. Your mind will relive the experience as you write and relive it again when you read your journal. A tripling effect. (University of Texas, "How Do I Love Thee, Let Me Count The Words")
3. Commit A Random Act of Kindness. Surprise someone a coffee, hold the door open for your coworkers, send a thank you note to an old teacher. (Lyubomirsky)
4. Meditate. Studies show meditation increases the activity in our pre-frontal cortext -- the part of the brain responsible for attention and focus. (Massachusetts General Hospital)
5. Write down 5 gratitudes. If you can be happy with simple things, it will be simple to be happy. The research here had students write down five gratitudes, events, or hassles. Those writing down gratitudes vastly outperformed the other two groups after ten weeks. (Emmons / McCullough)

#3 can be so easy. Just a simple "I like your [article of clothing]" to someone while you're standing in line.

In general is it kind to say something nice about a person's clothing? Just curious. 

It's not complimenting clothing, per se; it's saying something positive to someone else. 

People wear what they like, what they think looks good on them. Saying "Nice something" (not in a creepy way!) offers confirmation.

Is it better to compliment an aspect of that person such as smile or attitude?

Or is it better to stick to clothing?

I don't think there's a "better than". It's whatever is true. It's just verbalising what the brain's already thinking.

Ah, ok. I originally thought it was better to talk about something that is part of someone. 

But I appreciate your perspective. 

Style is a part of someone.  :)

Style is something we buy, whereas smiles and attitudes are something that's part of us. 

Style is an artistic expression that helps reveal how we see ourselves.

I see. I was reacting to the commercial aspect of style but you're right that it reflects artistic expression too. 

19 other Quora answers:

https://quora.com/What-5-things-can-someone-do-every-day-to-be-happy