Use a damp cloth to thoroughly clean the table surface and remove any dirt or grime. Doing this before you sand will give you a smoother finish.
To get rid of the varnish on the table, use a coarse sandpaper like 40 grit with an orbital sander. Sand the top and sides of the table. Make sure you regularly check the grit on the sandpaper and replace it when it's worn. When you're sanding, don't forget your safety equipment and put drop sheets on the floor.
As you sand, regularly brush the dust off the table. This is so you can see how much more sanding you need to do on the surface.
Continue sanding with the coarse grit sandpaper to strip the table back to its bare wood. Make sure you continue to check the grit on the sandpaper and replace it when necessary.
Once you've stripped the table back to bare wood, change the sandpaper to a finer grit, such as 240 grit. This will help you sand the table back until it's smooth. Remember to always sand with the grain and brush the dust off the table.
Wipe the table with mineral turpentine to remove any fine dust and residue that might still be on the table. When using turpentine put on your dust mask.
After the table is dry, it's time to apply the first coat of varnish. Stir the varnish thoroughly to get rid of any lumps. With a little varnish on your brush, apply it to the table, going with the grain. Keep an eye out for runs when you're working around an edge or into a join. Smooth any runs out with the brush as they occur. Let the first coat dry thoroughly.
Once the first coat of varnish has dried, give it a light sand with a fine sanding block. This will give you a smooth glossy finish. Wipe away any dust.
And there you go – a fantastic piece of wooden furniture restored to its former glory.