Before we get started, let's have a closer look at the image we will create, hopefully it will make you thirsty!

Step 1: First we need to create the background, set your foreground to light blue (#0785fb) and background to dark blue (#0763b9). Use the Gradient Tool with Radial Gradient and draw a long line from the bottom of your document

Next we have to find a suitable glass. I used this free image here

Use any selection tool to cut it out (Magic Wand Tool is the best in this case) and place it in your document, resize it if necessary

Step 2: Double click on this layer to bring up the Layer Style box, I used Inner Shadow and Inner Glowing to make it more realistic

    + Inner Shadow:

    + Inner Glow:

Step 3: We need some ice to make our drink cool but I prefer using water from this image

To cut water out from this image we need to go to Select > Color Range, use to sample the first specimen and then use to get next ones

Copy the selection areas and place them on your document

Step 4: Change this layer to Screen to bright it up a bit. Use the Eraser Tool with a hard brush to clear some water if you like, otherwise just ignore to the next step

Step 5: Look for a crazy image to decorate our work. I found one here

Go to Edit > Transform > Wrap to make it fit with our image

Move it to the bottom of the glass and change its Blending Mode to Screen, put this layer under your "glass" layer

Step 6:  Next we will add rain to the image. Create a new layer and fill it with black, go to Filter > Noise > Add Noise and use these settings: Amount 24%, Distribution Gaussian and tick on Monochromatic

Go to Image > Adjustments > Threshold to reduce its density with this setting

 Next go to Filter > Blur > Motion Blur and set an angle of 73^o and Distance of 11 pixels

Now change its Blending Mode to Screen, you will see it's raining ^_^

If you don't want to have rain on the glass, use the Eraser Tool to delete it (first you should select the glass area by Ctrl-left click on the "glass" layer)

Step 7: Find a nice flower image to decorate your glass, get one here

Cut this flower out and use the Transform Tool (go to Edit > Transform and choose Scale, Distort, Perspective or Warp) to customize your flowers

 Step 8: You may notice that our glass doesn't look real so we should change its lighting by going to Filter > Render > Lighting Effects but remember to select the glass layer first, adjust the lighting as following:

Now it looks better, right?

Step 9: We added some ice to our image at step 3 by using an available image. In fact we can do it with Photoshop, so in this step I will show you how.

 Use the Pen Tool to create a "S" shape like this. If you don't know how, read my Abstract Curve tutorial

 After that, set your foreground and background colors to white. Choose the Brush Tool on the left toolbar and click on the Brushes icon on the right toolbar, use these settings:

 With the Pen Tool is selected, right click on your document, choose Stroke Path and press OK

Press Esc twice to delete the path

 Step 10: Next we will add glowing effect to our drink. Press D to reset your colors, create a new layer and go to Filter > Render > Clouds to make some clouds. Go to Filter > Distort > Twirl and use this setting:

 Use the Elliptical Marquee Tool to select the center of this layer

 Go to Select > Modify > Feather and set a radius of 20 pixels. Press Ctrl-Shift-I to invert the selection and press Delete

Press Ctrl-D to deselect and change its Blending Mode to Color Dodge and move it near the glass

Step 11: Select the glass area by Ctrl-left click on the glass layer. Press Ctrl-Shift-I to invert the selection and press Delete

Step 12: Now to the last step! Go to Filter > Distort > Glass and use the default settings (Distortion 20, Smoothness 6, Texture Tiny Lens and Scaling 100%). That's all and here is the final result:

I hope the technique showed here will help you in your future projects. You may realize we didn't necessarily need to delete the outer of the twirl circle at step 10 since we deleted it at step 11. However, doing it will give us a more comprehensive way to see what we are creating

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