How to tell if this guy likes me?

Last year I met this guy, i was 16 at the time and he was 20, we met at this group thing and we went to a theme park. All the way round the theme park he was constantly talking to me asking me loads of questions and he was always really interested in what i said. I also caught him looking at me a couple of times and on the way back he insisted that i sat in his car so i could warm up because it was freezing. We did meet up a couple of times after that with a group of friends so it wasnt like a date or anything but still he would be really interested in everything i said. However he had to move to wales for uni and now has a girlfriend grrh. Because i am shy i felt like last time i didnt really give the impression that i liked him as well BUT he is coming back soon to live near where he used to and we are gunna meet up with the group again so any advice what i should look out for and what should i do about this whole situation? i still like him. thanks xx