I am pretty sure that it's best to take the plants out of the decorative pot, submerge it until the soil is fully saturated, and then remove it from the water and place it back in the decorative pot. Watering from above works fine too, but I've heard that it is best to keep the leaves dry if possible to prevent disease. I'm sure certain plants are pickier than others about this though Is there a specific type of plant you are asking about?
The best way to water most plants is to water them thoroughly, then allow them to almost dry out before watering again. This allows the plants to recieve plenty of water, but not drown in constant moisture. This is where watering plants from the bottom can be helpful. Letting the plants soak until saturation is often easier than reaching the saturation point watering from above. It is also better for most plants to have their leaves stay dry like Lisa mentioned. It is important to remember to remove the pot from the water once the soil has been sufficienltly saturated since the roots can be damaged if the pot is left in standing water for too long.