In this Adobe Photoshop tutorial you will learn the basics of making and defining a custom brush.

1.
First we need to define a shape to make the brush from, you can draw whatever you want, I just made a custom shape from Photoshops custom shapes tool, then used some tools to manipulate it a bit.

2.
Go to edit -> define brush preset and give it a name.
Now go to the custom brush tools menu (by default located at the right upper corner).

3.
In here we can make allot of changes to our new brush, remember one small change in the settings can give big results when you draw on stage, I tend to test the effect allot while making brush presets.

4.
Start by changing the shape dynamics, so it looks like in the image below, this is to give the brush a bit life by making them a bit different.

5.
Now in the brush tip shape make some changes as in the image below, to define the brush size and the distance between them.

6.
Also give it a some color dynamics this is to make the brush change in color, or and brightness.

7.
Now our brush is finished, go down to the right corner of the custom brush toolbar and click the small icon to save your new brush.

8.
Open a new document and draw some line with your new brush as I did, I changed the colors a couple of times to make it a bit interesting.
Keep in mind this tool is very powerful and effective to make allot of effects, but you may need to do some trial and error before you succeed.