Create Your Own Desktop Wallpaper Background in Illustrator

Create a rectangular box to fit the size of your canvas and fill it with blue gradient.

2. Create multiple screen gradient paths

Create another path to go in the corner with a nice curve on one side, you can match the colours or change them slightly and make them slightly more transparent than your background rectangle. You can repeat this step to create as many paths as you please.

3. Create wavy abstract lines

Now the fun part, draw two wavy/curvy lines with the pencil tool (N). Make then both white.

4. Blend the stroke lines

Go to Object > Blend > Blend Options, enter Specified Steps = 20. Then select your two stroke white lines you made with the pencil and go to Object > Blend > Make or press Ctrl+Alt+B. This will blend 2 white strokes and add random lines giving the two much greater depth and visual amusement.

You can also blend two lines that are different colours to achieve a gradient blend for added depth. Go crazy and blend two very different lines to see what effects you get.

You can repeat these steps to create as many blended lines as you desire and when finished you will have your very professional desktop background.