How can I apply a smooth finish on indoor wood?

I’m sorry you’re having woodworking trouble, but you shouldn’t feel badly. Most people have the same difficulties you do. Here’s a finishing recipe that I know works perfectly.

1. Get some oil-based urethane (I prefer a satin sheen) and a natural bristle brush and smooth the bare wood parallel with the grain using a progression of sandpapers up to 220-grit.
2. Moisten the surface with a wet rag to raise the wood grain, then let dry for 2 days.
3. Sand again with 220-grit sandpaper only, then vacuum all the particles off your project and entire finishing area.
4. Brush on a coat of unthinned urethane and let it dry for a day. Brush on another coat, and after it’s fully dry, sand the surface with 220-grit paper using a palm sander.
5. Vacuum again, coat again and sand again, for two more coats. That’ll be four in all.

Powder buff for finishing wood furniture. After all of the above you should find the surface is quite nice. Any remaining hardened dust particles can be removed by rubbing with 000 steel wool or a 3M rubbing pad. If you want a more refined finish, sand the area by hand with 400-grit wet/dry sandpaper, lubricated with plenty of water after the last coat. Finish by buffing the area with 0000 steel wool. You’ll get the best possible finish by using a random orbit sander over top of a super-fine 3M rubbing pad. It gives a spectacular result.

A word of caution: When sanding between coats, or with the wet/dry paper after all coats are down, be careful around corners. It’s very easy to sand right through the finish in these places, exposing bare wood.