How to find a four-leaf clover

Theres no guaranteed method. It just wouldn't work. But there ARE some things you can look for, and some things to be aware of.

The first step: look!

It seems simple enough, but the main reason people don't find four-leaf clovers is they aren't out looking. Don't be afraid to just stop and check out a patch of clover for a few minutes or so. And if you fine one, keep looking! A mutation in this plant tends to produce more than once in a patch! 

My record is 38 in one patch!

What to look for:
You want to look for clover that has something different about it. You won't find a four-leaf in plain clover. 
Most notable is the inverted V pattern that appears on each leaf 

but as aslo shown, sometimes clover just sports a different pattern! 

Can you find four-leaf clovers in any type of clover?

Well, this is the catch 22. It's highly unlikely that you will find one in red clover. Red Clover usually grows taller, vs white, which grows more as a ground cover. So while  I suggest you still check red, the place you wanna look most is white.

And be aware, there are other look alike plants that are not clover.
So just to name a couple common ones:

Oxalis.
A common plant found on sidewalks, in gardens, and basically anywhere. And while it is edible and really pretty, it is not clover.

Wood sorrel.
It comes in a variety of sizes, and it looks really cool, but it is definitely not clover.

Happy hunting!