We all have heard tragic stories from travellers who suffered diseases during trips and returned home sick, at the very least. However, you should not stay away from travelling to some of the world's best holiday destinations just because you fear such circumstances. There are ways to prevent yourself from being sick during your trip.
The first thing you should do is to check with disease control department for health advisories from the country or city you are visiting. Next, inform your physician ahead of time as to when and where you are travelling. Most likely, he will have health updates on your place of choice and give you medical advice and applicable vaccines. Your physician will most probably give you a list of prescription medicines for the trip. If so, ask a description or explanation of each medicine, so you will be able to answer customs officer why you are carrying such drugs.
Get in shape before going on a trip, especially if you intend to do lots of physical activities. Inform your family about your trip, and do not forget to leave your international roaming number to them so they will know how to contact you. If you have insurance coverage, confirm if you will be covered in the country you are travelling to. If not, it is best to get another one, as this can save you a lot of money in case of adverse events. Do pack a small first aid kit in your carry-on bag, which should include bandages, anti-bacterial ointments, as well as medicines for allergy, diarrhoea, and other common illnesses. Always have sun screen on your skin and water to drink to keep your body hydrated and your skin protected at all times.