The most important thing while traveling is your enjoyment of the experience be it studying, hiking, learning or just lying on the beach for some well-earned R&R. It is important to get a few practical things out of the way before you leave so there are no surprises when traveling with a buddy.
Your personal safety is paramount. Have a check-in system with your travel buddy. It can be a text at a certain time or meeting for a coffee or drink at a certain place and time. Check in with each other and follow basic rules of personal safety so your travel buddy doesn’t have to worry about you, get you out of the hospital or fish you out of jail.
Have a good time and do your own thing but be considerate that you are traveling with someone else who is also wanting to have a good time. You don’t have to be right all of the time, and your friend doesn’t have to insist on where to go all of the time. Being abroad is a good opportunity to open yourself up to new ideas and new experiences, leave the old curmudgeonly attitude and expectations of perfection at home.
Do use the Maps app on your phone if you go out on your own. Seeing an individual or two people huddled with a large paper map screams tourist and easy mark. Do your research before you leave the hotel and walk confidently. If you are lost, go into a shop and then take a look at your map.
Be up front about splitting costs. If your travel buddy only likes to eat full meals three times a day and you do not, find a compromise or do your own thing. You will likely have to pay tips for some services and possibly for tours. Be sure to plan for this in your expenses and also plan for cost sharing. If your friend likes to shop all of the time and you can’t afford it, go to the park instead and meet up later. There are tons of inexpensive or free things to do when traveling, starting with free walking tours and arboretums.
Having a hard time deciding on spending time together at a specific location? Flip a coin. Next decision gets to be made by the other person. If you are going to sulk all day about it though, then split up for the day and do your own thing.
The more upfront with your travel buddy you are about your trip goals and dreams, the better your trip will be for both of you. Sometimes the only way you will know if you are good travel buddies is to try it. I know several people who started as solo travelers and now have travel buddies across the US. Try it, be safe and have fun!