I remember when I first got in contact with other languages when I was younger; I felt it was awesome to be able to say a thing or two in an other language, and also, when you do the effort of saying something in an other language to a person from that place they greet you in a very different manner, they really appreciate it.
I've studied Finnish (I'm from a Swedish talking part of Finland), English, Spanish, Catalan and Portuguese, so I know them quite well. I also had to take a course in Latin, but I can't really remember much of it now, and I have to admit I'm forgetting some of my Finnish as I simply haven't used it in almost 7 years that I've been living in Spain. Danish and Norwegian are very similar to Swedish so I understand them quite well. I also shared a flat with some Italians so I know some Italian; before that one of the girls in the flat had a Turkish boyfriend so I picked up some Turkish, and I also know some phrases and some basic stuff in German (my sister's boyfriend is German), Dutch (know quite a few of them) and French (my other sister used to live there).
Obviously I don't know all of them as well as the first ones I mentioned, but I do feel like it's easier to learn more languages once you've learnt at least an other, as you can see similarities with other similar languages and that helps you to understand and learn faster. When I first came to Spain I knew very little, but nowadays people wouldn't notice that I'm not Spanish for my accent (my appearance does tell an other tale though haha). My biggest tip of learning an other language is to go to a place where they speak it. If you go there and they don't know e.g. English very well, you simply have to learn it. Being surrounded by it day and night helps a lot, there is no escape!