Agree with Brink. A few other ideas. If you have the time, rough cut your wood slightly oversize, stack and sticker it for a few weeks in the conditions the furniture will live. Then mill the wood to final dimensions and sticker it again for a few weeks. Always start from the beginning - use the jointer to flatten the boards then use the planer. When possible, try to take the same amount of wood from each surface. Do this for both millings. Make sure the wood is restrained while it is equibrialates. Every time you mill wood it exposes a new surface to the environment, and looses or gains some humidity. The stickereing process allows the wood to equilibrate under restraint and helps prevent warping. This is often impossible since you have what you have, but constructing the piece in a shop thatís about 7% relative humidity will help, since the average indoor RH is about that.
Donít count on the fact that the wood is Ďkiln driedí because itís moisture content will equilibrate to the environment. Wood will gain and lose moisture forever, and that is what causes warpage later. It can happen 100 years after you make the piece.
Then finish both surfaces of the table the same - same finish, same number of coats. Using a sealing finish like varnish or poly also slows down water exchange.
A breadboard end will also help if the design permits.