What is the best way to paint a cement patio?

Scrub it down with white vinegar before you paint (& rinse with water) the paint won't peel off later.

You can buy concrete paint. I used to refresh the paint on my concrete verandah on a regular basis when necessary. 😀

Check out Granite Grip by Behr sold at Home Depot.

Paint it to look like a rug or some other pattern. Here are some ideas:

https://www.google.com/search?q=diy+painting+concrete+porch&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiShouZt9jUAhUBEz4KHbhRANMQ_AUICygC&biw=1536&bih=757#tbm=isch&q=diy+pattern+painting+concrete+porch&spf=1498374291657

HTH

I painted my 14x24 with a deck paint that complicated the house brick...sort of a brick red. Power washed it first. After base coat was dry, sister and I used narrow, disposable foam brushes and free-handed simulated "grout lines," in a muted grey, creating the look of irregular flagstone. Covered it all with a coat of Thompson's Sealant. Has held up well, going into 5th summer. To free-hand, let one person start in a corner, working out a few lines, before making it a team effort.