To get a smooth finish with a paint sprayer, you can sand down the paint in between coats. Doing so will remove any rough parts of paint that would make the surface seem rough or uneven. For best results, use light grit sandpaper and only do this by hand. Not only will it remove small lumps of paint, but it can help to seal pores in the wood to create a glassy and smooth surface. When using your sandpaper, work parallel to the grains with long strokes. Once sanded, be sure to dust off any debris or dirt before spraying another coat on top. This helps to ensure that the paint is applied to a smooth surface and will dry smooth and evenly. You will also want to keep your arm straight when spraying your paint so that the lines apply uniform and evenly. This also helps to keep the paint smooth and should result in the desired finish! Don’t forget to check the user manual for your spray gun too, to see if the manufacturer has any extra tips or advice that you can use to achieve a smooth result!