VARIOUS TIPS AND DESTINATIONS IDEAS

Costs: define your costs, accommodation, hotel booking, flight tickets
Research what you might need there and how much it costs to eat outside to try their traditional or street food, museum sightseeing or other activities related to the country you are visiting.
Security: Research attentively your vacation; avoid places where there are health problems such as diseases or security concerns like war for example.
Language: being aware of what people are saying around you is considered a security tool. Maybe you need to consider countries that speak english as their second language or you can just use Google translate for basic needs.