After you have uploaded your Blockbench model to Sketchfab, a few steps are required to make the model look beautiful in the Sketchfab model viewer. Here are the the first steps, tricks and common issues:
Blurred Textures

All low resolution textures on Sketchfab will look blurred. You can fix this in a few simple steps:
- Open the 3D Settings of your model
- Open the Materials tab
- Select the material in the top area of the tab or by left clicking on the 3D model.
- Under PBR Maps, click on the Base Color texture.
- In the menu, set Filtering to Nearest
- Repeat for all materials

Transparency

Transparency in textures is disabled by default. You have to set the alpha channel of your texture as the source of transparency:
- Select the material as explained above
- In the Materials tab, scroll down to Opacity.
- Click on the texture and select your correct texture.
- Set the Filter mode to Nearest.

Ugly Camera Starting Position

By default the camera can spawn in random positions, resulting in an ugly thumbnail and a weird starting position.
- Open the 3D Settings
- Position the camera as you wish
- Click Save View in the top left corner of the viewport.