Understanding the Marquee Tool in Photoshop

Adobe Photoshop is the industry standard for photo creation and manipulation. Learning this amazing tool will both increase your productivity as well as increasing your awareness in what makes a good image great.
This tutorial will guide you in a step-by-step manner that, if followed correctly, will give you insight in how to use three of Photoshop's tools to create a custom image.
This tutorial has 15 images that accompany it to allow you to follow along visually

Create a new Photoshop document 800 pixels wide by 600 pixels high (Image 1)

(if needed) Turn your rulers on by left clicking on VIEW -> RULERS (Image 2)

Position your rulers at 50 and 700 length; 50 and 550 height (Image 3)

Using the rectangular marquee tool, create a rectangle in the center of your document based on the area created by your rulers (Image4)

Use SHIFT + BACKSPACE to bring up the color chooser box (Image5)

Use the drop down menu to select COLOR (Image 6)

Select RED and then click OK and then OK (Image7)

Use CTRL+D to deselect the area

Create a new layer using the new layer icon on the bottom of the layer palette

Name it White Stripe

use the rectangular marquee to create a narrow area across your red square ON THE NEW LAYER (Image 8)

Assuming your foreground color is white, hit ALT+ Backspace to fill the area with white

Tap CTRL+D to deselect the area

Right click on the Layer named "white stripe"

Left click on "Duplicate layer"

This layer will be named White Stripe Copy

Click OK

Using the MOVE TOOL, move the white stripe on the "White Stripe Copy" layer down a few cm

Right click on the Layer named "white stripe copy"

Left click on "Duplicate layer"

This layer will be named White Stripe Copy 2

Click OK

Using the MOVE TOOL, move the white stripe on the "White Stripe Copy2 " layer down a few cm

repeat as needed to produce this image (Image9)

Select the top layer, hold down SHIFT, select the bottom layer

Use CTRL+E to merge the layers

Create a new layer

Name it Blue Box

Create a blue box on the new layer (Image10)

Tap CTRL+D to deselect

Create a new layer

Name it Stars

Left click on the "custom shape tool" (Image11)

Make sure the fill pixels box is selected in the custom shape preferences (Image12)

From the custom shape preferences window, select the stars (Image13)

proceed to make stars (Image14)

When finished save your work

In this tutorial, you have learned how to use three of Photoshop's most valuable tools:
1. The Rectangular Marquee Tool
2. The Custom Shape Tool
3. The Custom Fill Dialog box

Using these tools will allow you to create incredibly unique images as well as manipluate images already created.