What's the best thing to take for motion sickness to prevent it?

Motion sickness. Atropine-like patch used behind the ear has been proven to be very effective (transderm scōp (transdermal scopolamine) patch is the name.
Avoidance. Avoidance is the best treatment but that can be difficult. Motion sickness is due to incongruous information from different sensory systems and some people are very susceptible to this. Avoiding or minimizng this conflct cures the symptoms. But sometimes that can't be avoided so medications like Meclizine or scopolamine are effective. Combination therapy (nausea + dizzy meds) are very helpful.

Related Questions

Help please? What is the best way to prevent motion sickness?

Scopolamine. You could try a Scopolamine patch. It is an anticholinergic medication that can limit the effects of motion sickness. It is applied around four hours prior to whatever event might cause your symptoms and is usually good for three days time.
Motion sickness. Some techniques include looking straight in the direction of the travel when in a car & if night-time close your eyes or nap, chew gum, fresh cool air, wearing a special eyewear called viban, & medications such as dramamine (dimenhydrinate) & meclizine, scopolamine transdermal patch, promethazine, ginger as crystals or tea.

Can any doc tell me what's the best way to prevent motion sickness?

Several methods. If it is going to be something like a cruise the scopolamine patch applied 3 hours before the ship sails and changed every 2 days works well. If not try to stare at a horizon line that helps keep the inner ear level.