Scale Pattern into Place
Start by scaling and rotating the pattern into place. In this example, we also Invert the pattern to Change Colors by pressing CTRL/CMD + I. Make sure to make the pattern a bit larger than the piece of clothing so it can be warped into place.
Use the Pen Tool to Cut Out Clothing
It is important to have an accurate cut out of the clothing, so the Pattern looks seamless. In this example, we use the Pen Tool to cut out the original shirt. Create a Pen path around the clothing by clicking and dragging to create Curves.
After completing the Pen path, right-click and turn it into a selection and feather the edge by 0.5 pixels. Next, load the selection as a Layer Mask for the Pattern, making it only visible where the original piece of clothing is.
Liquify the Pattern to Fit the Clothing
To make the Pattern look like it Flows with the fabric, it must be warped into place. Use the Liquify Tool to bring in the edges of the pattern, making it look like the pattern wraps around the piece of clothing.
To re-create folds of fabric, use the freeze mask Tool to paint over one-half of the fold. Then use the Forward Warp Tool to push the pattern under the freeze mask. If done correctly, it will look like the original pattern Curves around the folds of fabric.
Add Highlights and Shadows from Original Photo
The last step is to blend the pattern into the original image. In this example, we change the blend mode to ‘Multiply’ and lower the Opacity to 90%.
Next, add Shadows and Highlights from the original piece of clothing. Duplicate the Background layer and place it on top of the fabric layer. Right-click on the layer and select “create Clipping Mask”, then change the Blend Mode to ‘Multiply’.
To add Highlights, duplicate the Background layer and clip it to the fabric, just like the previous layer. This time set the Blend Mode to ‘Screen’. If needed, adjust the Brightness of this layer by using a Levels Adjustment – CTRL/CMD + L. Drag the black point slider to the right until the layer only appears over the Highlights.