If you begin to experience mild travel sickness, there are a number of techniques that you can try which do not involve medicine.
Reading or looking at a screen will often make symptoms much worse. A common remedy is to close your eyes or otherwise, focus on a stationary point in the distance such as on the horizon. In a car, it might be helpful to sit in the front seat. Try to avoid sitting backwards on a train or boat.
Try to find a seat or position in which you will move as little as possible. On a boat or plane, this will be towards the middle of the vessel. It is especially important to keep your head still, which you can do with pillows or head rests.
It is important to remain calm. Try to find a technique that will help you to relax, such as concentrating on music or your breathing. You might also want to try mental activities which will distract you from your sickness, such as listing the alphabet backwards or making mental lists.
It may help your symptoms to get fresh air, either by opening windows or by moving outside or to drink water. This will help you to remain cool and hydrated.
Be mindful of what you eat and drink before and during any journey. Foods which are spicy, heavy or rich in fat can make travel sickness worse. Consider staying away from alcohol before or during travel if you know you are susceptible to travel sickness.