Hello! In this tutorial, I’ll show you how to create a star shape and a triangle shape in Photoshop CS6. Follow the easy steps below, and watch the video tutorial.
Edit: See also the Custom Shapes in Photoshop: Star, Triangle, Heart & more here, and here.

Step 1. STAR
Create a new document and choose the Polygon Tool (U).

Set the stroke black and fill yellow (if you want your star stroked and filled).

On the right side of the Polygon Tool panel set sides to 5, and by pressing the screw shape button, choose an option star. You can draw now your star:

Step 2. TRIANGLE
Create a new document and choose the Polygon Tool (U).
Set the stroke black and fill red (choose colours which you like).
On the right side of the Polygon Tool panel set sides to 3, and by pressing the screw shape button, untick an option star. You can draw now your triangle:


Watch also the video tutorial:
Read also:
Custom Shapes in Photoshop: Star, Triangle, Heart & more
How to create the Gradient Text Effect in Photoshop?
How to make a sparkle brush in Photoshop?