[header] How to make a gradient in photoshop [title] Create the shape of your gradient with the selection tools. [step] These are the tools with the dotted lines, like the square selection tool or the lasso, that let you set aside a small area of your image. If you don't select anything, your gradient will simply fill the entire layer you're working on. 
[substeps] You can make gradients any shape, as long as you can create the selection. If you're just testing things out now, make a small square and work with that.