Assuming you are using a stain:
Just to add my $.02. Initial prep (sanding) is definitly the key to a good finish. Sand in progression from coarse to fine. At least down to 220 grit. Finer if your going for a high gloss finish. 330 -440 grit. or finer.
If your spraying your finish, several light coats are better than one heavy coat. If using a rag or paint brush, this varies, some people like to wipe off the excess after letting it sit for 5-15 Mins. (depending on temp & humidity) & some people like to wipe off the excess right away. If you are staining in a controlled climate ( A/C) you have more time to work with. Humidity will make a stain tack up quickly. I would allow 24 hours between coats for proper drying. Lightly sand in between coats to knock down the grain & any contanimants that may have gotten into the finish while drying. 000 or finer steel wool is good for this. Don't sand too much or you'll sand the through the stain. Don't forget a moisture barrier, (polyeurathane or sanding sealer or the like.) If you use a stain with polyeurathane already in it you don't really need the moisture barrier. I prefer to stain & poly in separate steps. (ol' skool I guess)