Use InDesign Frame Fitting Options to control how images scale, for example Fill Frame Proportionally.

Use Crop Amounts to adjust the image.

Use large text examples to size your text boxes correctly. This reduces the chance of text being cut off in the HTML preview.

Use Content Fitting and set Inset Spacing to ensure the entire font sits comfortably inside the box.

Keep text boxes too small. This can cause the Template Studio preview to cut off text.

Use simple shapes such as circles or rectangles.

Create a PDF for complex shapes before packaging.

Use free shapes created directly in InDesign. These may not convert correctly.

Create design elements directly on the pages.

Use Master Pages. The InDesign Server does not recognize Master Page content.

Use CMYK or RGB color models.

Add all used colors to Swatches.

Use transparent colors such as opacity 20 percent directly in InDesign.

Use Pantone colors.

Apply colors from the colorpicker without adding them to Swatches.

Create gradients in Photoshop or Illustrator.

Create a PDF of any shape that uses opacity lower than 100 percent.

Use shade effects from InDesign.

Create gradients for shapes or text directly in InDesign.

Use shapes with opacity lower than 100 percent created in InDesign.

Embed all fonts in the package.

Add Adobe or Google fonts manually to the package.

Leave fonts out of the package.

Use different styles or sizes inside the same textbox without tagging the text separately.

Avoid special characters in all filenames.

Use special characters in linked file names. These can cause conversion errors.

Test a simple version of your design first to confirm the conversion works as expected.

Keep shapes and effects as basic as possible to reduce processing issues.

Use consistent fonts and swatches across your document.

Review the final packaged folder to confirm all assets are included.