You may get .psd* file of "Sparkling Drink" Photoshop tutorial by making a payment. Put the tutorial title in "Add special instructions to seller" line of PayPal and it will be sent to you shortly.
Glass of cold sparkling drink.
Open image of a glass.
Right Click on Layer, select Layer from background > Ok.
Select the Glass, using Magnetic Lasso Tool.
Click on Quick Mask, correct the selected area, using black and white brushes one by one.
Fill the selected area with Gradient (Red/Transparent) in a new layer.
Adjust Overlay Blending Mode for the Layer with gradient.