It can be dang hard to get cute curls on short hair, but not with the right tools.
Most important is the right SIZE curling iron. For my not-quite-shoulder length hair I use a 1" iron. To decide what size curling iron is right for you to achieve the "boho look" you should be able to wrap your hair around the iron 2 times. If your hair is past the shoulders you will probably want to use an iron that is 1 1/4" to 1 1/2 inches.
You'll notice in the video that I can only wrap the bottom half of my hair around my iron one and a half times. That's okay because it's the bottom and just needs a slight wave.
A little trick I like to use is to twist the hair after I curl it. I feel like this does two things. First, by twisting it it kind of relaxes the curl to more of the bohemian wave instead of a ringlet. Second, it helps the curl cool down.
The rest is in the video. That's right my first video. Feel free to
Also near the end you will hear strange grunts, stretches and a sigh. I refer to these odds sounds as "the old man". It's Broc (our boxer). You can't see him but you will probably hear him ;-)