If you want to learn how to shape your eyebrows like the pros, then trim them if they need it. I've already trimmed my models eyebrow, to our right. You can see the difference this has already made.
A big mistake women make is not trimming their brows. When the eyebrow hair is long, sometimes women end up taking out too much hair when they really needed to take out bulk. So trim first!
Here's how to tell if you need to trim: Brush your eyebrows straight up, and if there are any hairs longer coming out of your natural shape on top, then trim it.
Yes, you can do this on your own, it's very simple. Use a fine-tooth regular comb or an eyebrow brush to push eyebrow hair up, and then just trim what is outside the shape with small scissors (preferably eyebrow scissors). If you have rather bushy eyebrows, then you'll need to take additional steps to remove more bulk, watch the eyebrow trimming step-by-step.