Make a Gradient?

This is going to seem amazingly obvious, but you make gradients using the Gradient tool (G). Click-and-drag it to create a gradient between where you started dragging and where you stop. By default, it builds a gradient going from your current Foreground color to your Background color. So, to change the color, just change your Foreground and Background colors. But, there are a bunch of other gradients to choose from. In the Options Bar, click on the down-facing arrow to the right of the gradient thumbnail to open the Gradient Picker, and you’ll see all the different default gradients you can choose from. Just click on the one you want. Of course, there are other sets of gradients you can load (just like there are other sets of brushes you can load). Click on the gear icon in the top right of the Gradient Picker and, in the bottom half of the pop-up menu that appears, you'll see all the different gradient sets you can add. When you choose a set to load, a dialog pops up asking if you want to replace (delete) the current gradients and use these instead, or just add (Append) these custom gradients to the end of the current set. You can return to the default set anytime, by choosing Reset Gradients from the same popup menu and it returns you to the default set of gradients.

TIP: CHOOSE FROM FIVE DIFFERENT STYLES OF GRADIENTS

There’s a linear gradient (a straight line between colors), a radial (circular) gradient, an angular gradient, a reflected gradient, and a diamond-shaped gradient. To choose one, click on its icon to the right of the gradient thumbnail in the Options Bar.